# Bass Management System Development



## Guest

Last week I posted my responses to a list of requirements for a dedicated home theater bass management system. My company has some interest in developing this sort of system.

There was some interest, so it seems like the next step is to start a thread to discuss it in more depth. Here we go. 

These are the requirements I listed last week:

~ Two independent channels.
Fine. Two independent inputs. How many independent outputs (in your wildest dreams)
~ A minimum of twelve parametric filters per channel (20 per channel is good too).
Fine. Only practicale limitation is processing artifacts and delays of multiple filters. Modern DSP's can handle this easily.
~ Channel coupling and series looping.
Probably not. All digital filtering can be accomplished in one pass at higher quality than two passes.
~ Three-way IN/OUT bypass.
Probably no analog bypass because we don't have analog outputs from the controller. Digital filters can certainly be cut in and out.
~ Input/output LED level indicators.
Definitely indicators on PC interface, possibly on front panel.
~ LED filter indicators for both channels.
Probably not.
~ Front panel display.
Very limited
~ Retain normal required buttons and jog dial.
Probably not, possible IR remote capability
~ 24-bit/96 kHz A/D and D/A converter powered by a 32-bit DSP.
Surely possible, although there needs to be a discussion on the recommended sampling rate for <250Hz signals.
~ Internal switch-mode power supply (100 - 240 V~ / 50-60hz).
Probably wall wart power supply with internal regulation.
~ Low power consumption.
Sure.
~ Adjustable input level (-10dBV / +4dBu) on rear.
Consumer line-level unbalanced input. Is more really required for a home theater box?
~ Hard bypass relay.
No.
~ Noise-free.
No fan.
~ 107db dynamic range.~ 0.007% THD.
On inputs and outputs.
~ High-quality components.~ High-quality construction.
Given
~ Balanced XLR inputs/outputs.
Required for home theater?
~ Soft power ON/OFF with selectable Auto-On detect via sub signal.
Probably
~ Eliminate turn-on thump and ground hum.
Sure, the digital interface will eliminate ground hum potential. The DSP can be responsible for pops.
~ Double insulated chassis with a two prong plug or a ground lift switch if needed to eliminate hum.
The external power supply will provide isolated 2 terminal power
~ Pure flat frequency response from 10hz to 20khz* (FBQ2496 is -3db @ 20hz).
Yes
~ Filter adjustment capabilities from 10hz to 20khz*.
Yes to below 20Hz (probably not to 20kHz as the system concept is for sub woofers).
~ Adjustable gain range from -24db to +16db for each filter.
Yes
~ Minimum of 4 to 6 memory presets.
Yes
~ Replace ¼ inch inputs/outputs with RCA inputs/outputs.
Yes
~ Simple shelf filter… (i.e. selectable linear boost between two selectable frequencies).
Yes
~ Selectable and/or variable 6db-48db/octave subsonic roll-off filter from 35hz to 10hz (minimum 5hz increments).
Yes
~ Time delay from 0 to 30msec or 1 foot increments w/ 0.1 foot fine up to 30 feet.
Yes, independent for each output, is 30 feet enough?
~ Variable phase correction/adjustment from 0-180.
Yes
~ Front panel USB and/or RS-232 interface for MIDI port (place under small flip cover like on computers).
1394
~ Dimmable front panel LED's / lights with OFF option.
Off option for free.
~ Soft blue and/or green LED's on front panel vs. red.
few LEDs
~ Offer unit in black or silver… if not optional, offer only in black.
black
~ Revamp chassis for home theater consumer appearance vs. pro-audio style.
~ Allow mounting brackets to be optional (include unattached).
~ Enclose/fill gaps on sides if mounting brackets are removed.
~ Add rubber feet to allow placement on top of other equipment.
~ Remove graphic design from top of unit.
home theater friendly
~ One year warranty.
certainly
~ Anti-clipping mechanism with higher dynamic peak input before clipping.
24 bit dynamic range may have to do. Clipping indication available.
~ Frequency readout in hertz instead of base + fine… (1hz increments w/ 0.1hz fine increments).
Yes, on PC application.
~ Bandwidth readout in octaves (1/3,1/6,1/24,1/1, etc.) or hertz (2hz,5hz,12hz,etc.) instead of 1/60, 10/60, 60/60, etc.
Yes, on PC application, ideally notation will agree with REW.
~ Front panel volume/gain to control output level to sub.
Probably not, possibly available over IR control.
~ Ability to slave multiple units together.
Unlikely, hopefully it wouldn't be necessary. Can you describe the need?
~ Linkwitz transform circuit.
Can't this be done with a digital filter? Looks like a shelf filter.
~ Detachable power cord.
Yes, wall wart.
~ Individual crossover filters (Butterworth, Bessel, Linkwitz-Riley) per channel w/ selectable roll-off 6db-48db/octave.
Digital crossover filters?
~ Adjustable/variable crossover range (low pass and high pass from 20hz to 200hz and w/ bypass).
Yes, if digital filters are acceptable
~ Built-in RTA mic/line input w/ phantom power and w/ GAIN control.
Yes, this would be XLR?
~ Built-in SPL meter with selectable dBA/dBC/OFF weighting.
Digital
~ Built-in test tones (sine waves - individual 1hz increments and sweep from 5hz to 400hz or 5hz to 20khz).
Yes
~ Separate RCA mic monitoring and test tone output to allow for computer program monitoring.
Don't quite understand, certainly computer program monitoring is a priority.
~ Locate RTA mic/line inputs and RCA monitoring outputs on the front face plate under a small flip cover.
possibly
~ Video output for monitoring the display would be nice, but the cost factor may prohibit this.
Display on computer connected via 1394.
~ Video display instead of LED's… (dimmable and selectable OFF).
no, but graphically rich PC interface available
~ Small and simple 6 button wireless IR remote with discrete ON/OFF buttons and Preset 1,2,3,4 buttons.
IR control could replace many front panel buttons, and interface with home theater control systems.
~ Rear IR jack for remote control… to use with repeaters.
Yes
~ Add volume/gain control button to remote if feature is made available.
More likely on remote than on front panel
~ Add other control buttons to remote if cost feasible.
Given IR control, more buttons is not a cost issue. We probably wouldn't include a remote, more likely to offer a configurations for Harmony and other programmable remotes. I know my theater doesn't need another remote!


I can't commit to this product yet, but feedback would definatly help define a possible product and validate the potential market, both useful in our business case development.

Barry


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## Guest

I was unaware of using professional amplifiers for DIY subwoofers. That makes sense. I would expect to provide a different output module with XLR connections if there was a demand. Keeping the unbalanced output module inexpensive is a priority.

Is there a similar situation for source signals on XLR? I assumed most dolby decoder type boxes would be unbalanced.

Barry


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## Guest

In the interest of full disclosure I work with Quantum Parametrics. 
To date we have exclusivly produced 1394 test equipment. As I mentioned previously, we are introducing a new 1394 protocol standard and are looking for demonstration product applications. 

Initially the bass management system seems a good fit both in technology, complexity, and market size.

It's much too soon to say how or if or who might produce this product. I'm just saying I'm interested in discussing it.


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## Sonnie

Hopefully we can get some worthy discussion for you... I know we all have the desire to see a unit produced that will fit our needs better than what is being offered at this time.


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## brucek

> I would expect to provide a different output module with XLR connections if there was a demand. Keeping the unbalanced output module inexpensive is a priority.
> 
> Is there a similar situation for source signals on XLR? I assumed most dolby decoder type boxes would be unbalanced.


I don't know what you mean by dolby decoder type boxes.

The unit has to be able to accept both unbalanced and balanced inputs to the two channels. The input to the device will be fed line level signals from home theater processors, receivers, preamps that have low output impedance (usually less than 100 ohms). The device has to have high input impedance that accepts a switchable range of levels since there are two quasi standards in the industry (-10dBV and +4dBu).

The balanced connections can be TRS or XLR and the unbalanced RCA type.

The output of the device (low output impedance) will be feeding subwoofers with their own amplifiers, or DIY subwoofers with external amplifiers (high input impedance devices). Some of these devices accept balanced and some unbalanced. Again the levels usually conform to one of the two standards.

Here's an FBQ2496 from Behringer.
You can download its PDF and look at the specs etc.

Here's the type of specs we would be looking for. (except most people would want the unbalanced connection as an RCA rather than an auto detect TS jack..









brucek


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## Guest

Thanks for the input. I'm warming to your position, but I'm not quite there yet .

The cost goal is going to be difficult to meet. XLR connectors alone can cost $5 each. My estimate is 95% of the customers for this device wouldn't use any XLR inputs (feel free to make a better estimate). That means the system would cost at least an extra $25 for something that wouldn't add any value to 95% of the customers. On the other hand, an XLR for a calibration mic could possibly add value to 95% of the customers.

On the bright side is the flexibility of the Firewire architecture of this proposed system. I consider it the true professional audio interface. If a high end customer saw value in implementing a balanced input to the system he could attach another device like a M-Audio Solo or Miglia HA02 ($120 or less). These devices could digitize the balanced signals in a very high quality manner and pass them to the bass management device. I think the Miglia even does the soft clipping you were interested in. If this really turned out to be a popular option for the system, we could develop simple lower cost devices to perform this same function. The Miglia and M-Audio devices include many other functions.

A customer could presumably gang as many of these devices as necessary to satisfy all his input requirements. The memory in the main system would select the appropriate input for each setup. In my future dream world, all the source devices are providing digital streams over Firewire and no converters are necessary until the amplifier.

All this flexibility comes nearly free with this system architecture. The main unit stays as low cost as possible with 2 unbalanced inputs that add value for 99% of the customers. Even most of the XLR users will likely have an unbalanced device they want to hook up.

I'm still open to the probability I'm missing something. Please feel free to correct any of my assumptions. I appreciate you sharing your experience and I'm willing to adjust to compelling arguments.

Is this really the only issue you find on the list of requirements? I can't imagine it's so close to ideal on the first pass! Would you like to discuss DSP options?

Barry


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## Sonnie

Personally I would not be offended it it did not have XLR inputs/outputs. There is quite a lot of fine equipment out there that doesn't have XLR and generally they will all have RCA... plus we are talking sub frequencies, so I don't see it being a make or break issue myself, but I could be missing something. :huh:

Thus far let's consider the features on the list you object or somewhat object to:

~ Channel coupling and series looping.
Probably not. All digital filtering can be accomplished in one pass at higher quality than two passes.

~ Three-way IN/OUT bypass.
Probably no analog bypass because we don't have analog outputs from the controller. Digital filters can certainly be cut in and out.

~ LED filter indicators for both channels.
Probably not.

~ Retain normal required buttons and jog dial.
Probably not, possible IR remote capability

~ Front panel display.
Very limited

~ Hard bypass relay.
No.

~ Front panel volume/gain to control output level to sub.
Probably not, possibly available over IR control.

~ Linkwitz transform circuit.
Can't this be done with a digital filter? Looks like a shelf filter.

~ Separate RCA mic monitoring and test tone output to allow for computer program monitoring.
Don't quite understand, certainly computer program monitoring is a priority.


These are really all we need to discuss.


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## Sonnie

~ Channel coupling and series looping.
Probably not. All digital filtering can be accomplished in one pass at higher quality than two passes.

This probably isn't a big deal. I don't really understand the digital limitations of looping one channel to the next for double the filters, but with a dozen filters per channel, I think most everyone would be satisfied. 

If I'm remembering correctly, coupling simply allows both sets of channel filters to be input simultaneously. With REW automatically loading the filters into either channel, I don't see this as a major loss.


~ Three-way IN/OUT bypass.
Probably no analog bypass because we don't have analog outputs from the controller. Digital filters can certainly be cut in and out.

~ Hard bypass relay.
No.

I think these go together. I can't remember what the issue was with needing a hard bypass relay. 

How would we set the input levels without bypass... again, I'm sure I down understand the process completely, but for the average guy like me, I'm seeing this is something we need to do (set input levels). 

So when the unit is OUT, does the signal still get passed on to the sub?



~ LED filter indicators for both channels.
Probably not.

~ Front panel display.
Very limited

These tie in together. I assume by some of your other remarks that there will be some sort of monitor output and/or computer connection for monitoring/viewing the settings. So having a computer nearby is now a necessity and the manual method of doing things is out the door.




~ Retain normal required buttons and jog dial.
Probably not, possible IR remote capability

~ Front panel volume/gain to control output level to sub.
Probably not, possibly available over IR control.

We will either have to have these on the front panel or on the remote. Somehow we have to be able to make the adjustments, input filters, etc. OR, are you suggesting this will all be done via computer program that you will furnish?

I'm confused about these.



~ Linkwitz transform circuit.
Can't this be done with a digital filter? Looks like a shelf filter.

Not a major loss IMO. This was suggested because it is supposedly a relatively inexpensive add-on, but I don't understand how it all works... others can chime in on it.




~ Separate RCA mic monitoring and test tone output to allow for computer program monitoring.
Don't quite understand, certainly computer program monitoring is a priority.


If we have a mic input and SPL meter built in to the unit... that information has to get to a source that can read and display the information it measures. I guess maybe it's a given that this would be included.


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## Guest

Thanks for breaking it down.

I'm still no fan of series looping. If channel coupling means running the same filters on both channels, that seems very easy to accomplish.

The two bypass issues do go together. A wired bypass breaks the architecture. 

Input level setup is a good point. I would expect this to be the first step of calibration. I envision a process step where a signal is applied to the system and the system reports any signs of clipping. Then the input must be lowered or raised until maximum dynamic range is achieved without clipping. I'll bet someone can find holes in this strategy. Hopefully you can also recommend a fix!

I don't see why one of the presets couldn't be OUT. In this mode no signal would be sent to the sub. Does this serve the OUT request? I thought OUT meant no change to the signal (even though it's being A/D'd and D/A'd.) Certainly another preset could implement this "no processing" option.

Let me expand on the computer interface. My concept is that all setup would be controlled from a computer connected via Firewire. It seems to me that calibration with REW already requires a computer. Additionally requiring a Firewire interface wouldn't be a show stopper if it adds the value I expect it to. In the simplest case the computer application could just be knobs and buttons like a physical interface (the manual method), but I imagine there is great opportunity to automate tasks and integrate with other applications like REW. The goal is to reduce user interface cost on the hardware, and enable user interface development on PC's where it is easier, less expensive, and more flexible. I'm sure attracted to the Java multi-platform approach of REW.

So yes, setup would be done on a computer running a provided application.

After setup, the computer would not be required for operation. Hopefully there will be a small list of required actions during operation. Currently I can only think of one "change preset". I'll bet we find at least a few others that will be needed during operation. These actions must be supported by front panel buttons or IR control. I also need a list of feedback (LEDs) required during operation. That list needs to be as short a possible to keep costs down and focused on operation, not setup.

SPL information from the microphone would also be sent to the computer for display and use in the setup application.


Does all that make the system more attractive or less?


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## brucek

> My concept is that all setup would be controlled from a computer connected via Firewire.


A lot of people don't have Firewire interfaces on their PC's that they use for REW. I would much rather see USB for the PC connection.



> I don't see why one of the presets couldn't be OUT


You're a bit confused on the meaning. 
The BFD has a button on the front panel that is labelled IN/OUT.
The LED on this switch indicates its present functionality.
LED on = Filters engaged, VU meters showing output signal levels.
LED off = Filters disengaged, VU meters showing output signal levels.
LED flashing = Filters disengaged, VU meters showing input signal levels..
We use the switch to test filters in or out and also to set the input level. 
We do this by playing a bass heavy movie at the loudest volume we would ever have the sound system, and then we adjust the receiver/processors subwoofer trim up or down to have the signal level just showing a yellow LED and the RED LED flashing. We hope for the best S/N and dynamic range once that's set.
Yes, it's a crude way to set the input level, but you have to understand that this isn't a fixed line level as would come from a CD player. This level is at the mercy of the receivers volume control. We need to have monitoring on input and output for clipping.



> My estimate is 95% of the customers for this device wouldn't use any XLR inputs


Anyone with a DIY IB or subwoofer would likely have a pro amp. These use XLR connectors, balanced inputs. Some allow the use of unbalanced inputs by using a TS plug, but adding the likelihood of hum. Subwoofer are very prone to hum since they amplify that frequency range so well.

In addition there are those that have processors with XLR balanced outputs. There's a certain pride and admitted insanity about audiophiles that you may not be aware of. Most wouldn't be interested in using a "converter" to switch to unbalanced..... Just my opinion though.

brucek


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## Otto

Hi Barry,

Interesting that you're considering taking on this project... There's a lot to go through in the list of desired features. I'd like to come back to some of those later, but I'll offer a few comments now.

brucek is right about firewire -- few have it. I see that your company is into it, and I would still purchase a device that has firewire, but I think there should be other control inputs as well. USB is, of course, a very popular interface. I'm also tired of dealing with RS-232. I'm trying to implement PC control of my Outlaw 990 via RS-232, and it's been nothing but a headache to get that working. My Dell, and another I just ordered have no option for RS-232 (USB to RS-232 sometimes works...). If you will only do firewire, I would still be interested.

I'm also a fan of balanced I/O, and favor XLR for its positive fit, locking mechanism and cool look. Subwoofer cable runs can sometimes go for quite a distance, and I like the improved SNR with balanced signalling. My preamp has balanced outs, and I use a pro amp for my IB, so I'm balanced all the way around.

I think you already said "OK", but I would think it's got to go to at least 10 Hz.

It sounds like you're already considering it, but IR remote control is an *absolute must*, IMO. 

A general output level control would be very important to me as well. brucek described the current method for setting input level accurately as to avoid clipping and maintain dynamic range. Giving us a sub level control on the back end will allow us to _not_ modify our input level by tweaking our preamp's sub out level. For me, it would be OK if this were only controllable through IR remote.

I know you want to keep the front display simple. I would like it to indicate at least a few things -- output level, filters on/off, current program. I dont' think I care too much about it representing how many filters I'm using for a particular program, but it wouldn't hurt, either.

That's it for now. Thanks for considering this project.


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## brucek

> ~ Built-in RTA mic/line input w/ phantom power and w/ GAIN control.
> 
> ~ Built-in SPL meter with selectable dBA/dBC/OFF weighting.
> 
> ~ Built-in test tones (sine waves - individual 1hz increments and sweep from 5hz to 400hz or 5hz to 20khz).


Personally, I see no need for this feature (expensive or otherwise). What would it be good for.

We already use REW for setting up the EQ filters. It's an amazing program for free. It does everything you would ever want (and if it doesn't - it will).

REW uses the receivers/processors bass management and crossover when setting up the subwoofer portion and the mains portion. It allows you to add the mains and adjust phase placement etc, to get the nicest transition at the crossover. It's a true in-situation signal from the bass management for redirected bass.

I see very little justification for a built in RTA. Once you're finished, would you not then have to light up REW anyway.

I'd take the funds spent on that feature to get balanced connections and a USB port to load my filters from REW. The 1124P is $129.... I would think for $250-$300 we would at least have the same functionality.

brucek


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## Sonnie

I like the idea of having both Firewire and USB.... and I further like the idea of eliminating the mic input, SPL meter and test tones. I also see the point where XLR are probably going to be needed, although not by me, but by more than I originally was thinking. 

Surely we could get Firewire, USB and XLR by eliminating the mic input with mic amp and phantom power supply, SPL meter and built-in test tones.


I also agree that we must be able to *filter* down to 10Hz and I second the remote being a must.


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## Guest

Once again, thanks for the feedback. I'll get to the points.

Firewire. Sorry, but this is the one issue I'm not flexible on. It's quick and straight forward for us to develop a firewire device and it supports our strategic goals. USB and RS-232 are not on my path. PCI and PCMCIA firewire cards are less than $20. Apple computers all come with Firewire installed. If this becomes a show stopper, I'll have to look for another application.

XLR (balanced inputs) I can be conviced here, but I'm not quite yet. Perhaps I should have described the add-on boxes I mentioned previously. They are not adaptors. They are professional quality D/As and A/Ds from professional audio equipment manufacturers. They can take in a balanced signal over XLR's and digitize it in a high quality fashion, then hand the stream to the bass managment system over the Firewire interface (skipping the bass management system's unbalanced A/D's). That is how we could satisfy the most quality concious users. (BYO A/D) The adaptor route is also valid, but I understand it would not satisfy the balanced type of customer. 

XLR (balanced outputs) You've won, I'm on the team ! The architecture I'm proposing is Firewire digital audio to the sub woofer, with a small converter at the speaker. Supplying seperate balanced and unbalanced speaker (amplifier) modules is not difficult. The customer could choose.

Mic input -- I'm also flexible here. Here is my thought process. No one seems fully satisfied with the RS meters and thier calibration file requirements. Better meters are very expensive. I'm also suprised that the XLR crowd is satsfied taking their measurements from a RS mic over an unbalanced input into a PC sound card of questionable quality. I thought that providing a powered, balanced, xlr input would pave the path to using a higher quality mic over a higher quality connection, for about the same cost as the RS meter. If I'm wrong and this isn't a compelling advantage, I'd rather save the money. If I'm correct, adding this feature could add $100 in value to many customers (who don't already own meters) at a much lower cost when integrated into the system.

Test tones are free. Can't trade them for anything.

SPL meter is free. (Mic input is not) I don't care if the bass management system generates the SPL information, or just forwards the waveform to REW and REW calculates it. Wherever the job can be done best. My point was that the bass management system combined with a mic, combined with REW would not require another SPL meter.

RTA -- frankly I passed over that acronym when I read your requirements list:whistling: and I focused on the mic input. I'm not interested in repeating or replacing REW functionality. Everyone seems very happy with REW. I have no desire to reinvent it. My goal is to provide a hardware platform that provides REW better data, and makes it easier for the user to apply the data generated by REW. As I understand it REW can already use a Firewire "sound card". The bass management unit could just provide REW the functionality of a high quality sound card in the simplest implementation. I've read several comments from laptop users without line-in. This enables a laptop (with firewire) to use REW.

I have to agree, if you don't have IR control, you don't have a home theater product. I'd like to skip it, but that seems irrational.

Calibration, sounds like I'm on the right track. Your description of the current process sounds familiar. I'm just saying I think we could make that same process a little more accurate and repeatable than watching for yellow lights.

Current front panel indicator requirements.

signal level (2 led bars)
current mode / preset (3 seven segment leds) 

Current front panel control requirements

Mode change button

There is another option I should mention. The system could be a PCI card that fits into a home theater PC. This would greatly reduce cost! It's my impression that HTPC's are not popular enough yet to support this. There are other issues also. Comments?


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## DrWho

What is the intended purpose of this device? I'm just seeing a lot of random features thrown together??? What exactly do you want it to do? What price point is being aimed for?

Right now I get the impression that you're trying to cram all of the hardware involved with REW/BFD into a single package? So basically a device for taking measurements and then applying the filters to the signal path?

I would propose making a firewire shell with drop-in modules, allowing the end-user to fully customize their purchase. For example, I already have the ability to take measurements so I don't need to purchase a module for connecting a mic to the computer. Each module would contain its own DSP, analog input/output stage and then connect to a digital bus inside the shell. Basically, the shell is just handling communication with the computer and providing any necessary signal routing. The only additional costs involved would be the mounting configuration and then matrixing the digital signals. Hmmm...sounds like a good lab project. Just throwing ideas out there.

One other advantage is the ability to sell at different performance points. There is the user that wants the bare bones approach (which you seem to be targetting), and then there are the users that want the absolute in sound quality.

-------------------

As far as maximum input/output capability...I think the most extreme case would be a stereo sub + LFE application. The L/R preouts from the receiver would be sent to the device and output band-limited signals to the LR mains and the LR subwoofers (basically taking an (N)-Way speaker and converting it into an (N+1)-Way speaker). The LFE output would be sent to the device and then output to the dedicated LFE subwoofer.

Going one step further, you might want the device to be capable of bi-amping the mains (or tri- or quad-...). This would take the 3in-5out configuration above and turn it into 3in-7out for bi-amped mains, or 3in-9out for tri-amped mains.

And then even one step further - you might want the device to be capable of handling all of the bass management for a 7.1 system, which would require a minimum 8in-8out. With the triple subwoofer configuration, it would require 8in-10out. If you biamp every speaker, then you're looking at 8in-17out...

Crazy? Perhaps. At some point it will become more cost-effective to implement all these features inside a dedicated pre/pro that way there's less conversions between analog and digital, not to mention less redundancy of circuits (since most of these features are built into the dsp's in pre/pros).

A more feasible alternative would be a subwoofer system using two subs...the user can choose to run each off the mono LFE send, or perhaps try to mix the LR with the LFE for music listening, etc etc...


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## DrWho

Two quick questions:

1) What is the purpose of having a remote?

2) Since this device is intended for home audio, couldn't there be a video output for on-screen display? It would probably be cheaper and then the front-panel could be left entirely blank.


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## Sonnie

bvwj said:


> Firewire. Sorry, but this is the one issue I'm not flexible on. It's quick and straight forward for us to develop a firewire device and it supports our strategic goals. USB and RS-232 are not on my path. PCI and PCMCIA firewire cards are less than $20. Apple computers all come with Firewire installed. If this becomes a show stopper, I'll have to look for another application.


Well my laptop has Firewire and I think most newer PCs and Laptops have Firewire, but the older ones would have to buy the adaptor unless you could include USB in addition to Firewire.



bvwj said:


> There is another option I should mention. The system could be a PCI card that fits into a home theater PC. This would greatly reduce cost!


:scratch: You lost me on that one. If it's what I'm thinking, that would make absolutely no sense whatsoever. I don't want to have to keep a computer in my HT room.


bvwj said:


> Mic input -- I'm also flexible here. Here is my thought process. No one seems fully satisfied with the RS meters and thier calibration file requirements. Better meters are very expensive. I'm also suprised that the XLR crowd is satsfied taking their measurements from a RS mic over an unbalanced input into a PC sound card of questionable quality. I thought that providing a powered, balanced, xlr input would pave the path to using a higher quality mic over a higher quality connection, for about the same cost as the RS meter. If I'm wrong and this isn't a compelling advantage, I'd rather save the money. If I'm correct, adding this feature could add $100 in value to many customers (who don't already own meters) at a much lower cost when integrated into the system.


Since you say the SPL meter is free, unless you throw in a microphone, then the mic input, provided it has phantom power, is only worth 50 bucks, because that is what is cost us. We can buy the ECM8000 mic and a mic amp with phantom power for 100 bucks. We can buy the Galaxy 140 SPL meter for 100 bucks and it needs no mic amp. Both of the latter are good enough and much better than the RS meter.

IOW, if you include the mic input and provided it has phantom power, you save us 50 bucks... we still gotta spend at least 50 bucks more on a mic. 



DrWho said:


> What is the intended purpose of this device? I'm just seeing a lot of random features thrown together??? What exactly do you want it to do? What price point is being aimed for?


It would replace the BFD as a parametric EQ... allowing filtering down to 10Hz and adding a few of the features (x-over, phase adj, SPL meter, etc.) we have proposed previously to Behringer for a new unit. $250 seems to be the price point we are looking at here.


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## Guest

It may look like a list of random features, but I think that's because we share so many common goals, that we just started in quibbling over details of the extended feature set. Thanks for slowing us down. Maybe this will help get everyone on the same page.

Goal
Affordable, high quality system to enable tuning low frequency signals for non-ideal home theater environments. (Affordable and high quality just have to duke it out until we agree on the mix.)

Core Benefits (in order) I think we pretty much agree on these
1. Parametric EQ -- Enhanced for low frequencies down to 10Hz. If this was all we did, it wouldn't add much benefit over existing solutions.

2. Time Delay -- Multiple sub systems need time delay. I'm unaware of a current affordable integrated solution.

3. Additional filtering -- crossover, phase adjust. Also valuable for multi sub systems.

4. Compatible with REW -- leveraging existing work in this market.

Architecture benefits-- This is the value I can add to the core benefits, this separates our product from other potential solutions.
1. Firewire backbone
2. Digital to the sub woofer.
3. Firewire PC interface for setup and control
4. Firewire expansion potential (multiple I/O capability)
5. Daisy chain signal routing to speakers
6. Firewire audio data transfer to PC for calibration.

Market requirements
1. Common I/O (we're discussing what common is)
2. Home Theater friendly (case appearance, IR control)
3. Simplified setup (REW integration, input/clipping calibration)
4. Price (discussed below)

Value Added Features
1. SPL mic input (under consideration)
2.  Configuration Display (LED's or other, some display necessary)
3. Real Time Analysis (Not under consideration)

It appears to me that parametric eq and time delay currently cost about $250 and come in separate units not specifically designed for the home theater environment. That's why I think the price ceiling is about $250. I believe if we can match that price and include the other features above, we can be competitive. As an unknown company, it's not enough to just match what's available.

I'm also trying to understand exactly who the market is. My guess is that people who would spend the cash for this solution have already invested over $1000 in a sub-woofer, or in multiple sub-woofers. There seems to be a significant market for sub-woofers in this price range. I expect people in this range would consider paying another $250 to make their investment sound as good as possible.

Of course, the farther below $250 we can reach, the farther down the sub-woofer price curve we can reach.

I'm sure at the very top of the range a people who would never want their audio signals digitized. I can't help them.

That's what I think we are discussing. Your comments so far have helped me sharpen this vision. Thanks.


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## Guest

IR appears required. The only other reasonable input is front panel buttons and that doesn't seem home theater frendly to me. 

Of course Firewire control is available, but that doesn't help without a computer connected.

I just imagine people will at least want to change the preset without leaving their chair.

On screen display doesn't solve the command input problem. A remote would still be required to navigate the OSD.

I think OSD would be more trouble that its worth. Discussing 2 different audio input standards is thorny enough. I can't imagine convering the 3 or 4 video standards my theater would need just for OSD from an equalizer.

If anyone has better control options than IR I'm definately interested.


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## Guest

I mis-spoke in previous posts. The Miglia HA-02 and the M-Audio Solo don't have balanced inputs. The M-Audio solo does have a balanced, phantom power mic input.

To get balanced input to firewire appears to be about a $300 box.

I'm investigating the recommended modular input approach. I may be able to accomplish that without adding too much cost.


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## Guest

I only offered up the idea of a PC card to check on the state of home theatre PC's. If you were all using them it might be a solution. 

I suspected that they aren't widely used yet, but you have surprised me on other issues.

I'm moving forward with an independent self contained unit.


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## Otto

bvwj said:


> Digital to the sub woofer.


I'm not sure what that means...



> It appears to me that parametric eq and time delay currently cost about $250 and come in separate units


Time delay is a feature of most receivers and pre/pros. Phase control is also offered on some stand-alone subs. Allowing time delay for multiple sub outputs would be kinda neat. I'd imagine this is pretty easy to implement, so go for it. That said, I don't think it will get all that much use (I could be wrong here...).




> Of course, the farther below $250 we can reach, the farther down the sub-woofer price curve we can reach.


Agreed. Shoot for $199. I'm thinking that if your initial goal is $250, it'll be real easy to creep up to $299. Also, everyone who posted in this thread should be offered one for free for their input to the development of this versatile product! :bigsmile: 

I'm OK with the firewire interface to implement PC control. It looks like there are USB-to-firewire adapters readily available on eBay (well under $20 shipped). Would your product work with that type of device? I'm assuming "yes" because the device takes care of the signalling changes and presents a valid firewire protocol to your interface. I'm asking because I just had a problem with another device NOT working with a USB to RS-232 adapter. I'm not sure why this did not work, but they said "yeah, sometimes those things don't work with our product." I think it may be because the original RS-232 protocol used 12V switching, and the adapter uses 5V. IMHO, they should have accounted for that and implemented it to work with the 5V device. I'm out of PCI slots, so I can't put another card in (well, I have a PCI-express x1, but that's it). Anyway, if you can get it to work with the USB-to-firewire adapter, I'm sold on the interface.

Good to hear about the IR. I think that would be a real showstopper for many.

You're also correct about the OSD. Too much trouble and cost for you with minimal payback. We can control the BFD with MIDI, and I rarely touch the thing -- everything is done from the PC.



> To get balanced input to firewire appears to be about a $300 box.


I'm not sure what that means. Are you saying you want to convert analog balanced input to digital firewire audio? Why? I think I've misunderstood... Actually, let me ask a question: are you intending to use the firewire interface for anything other than PC/device control interface? Are you intending to run audio over firewire?



> I'm moving forward with an independent self contained unit.


Yep, that's the right direction. Not too many have dedicated HTPCs.

So, what's your background with HT? Do you have any interest in seeing a system like that (esp the BFD part) in action?

Thanks again for all your effort toward this device.


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## Guest

I understand my concept is very different from the current approach. I'll take another stab at explaining. Yes, I am talking about audio over Firewire in addition to the PC interface. This enables many things.

1. Flexible inputs -- Adding another or a different type of input is a simple as adding a Firewire A/D. A/D fanatics could spend as much as they want on the A/D of their dreams.

2. Digital to the speaker (sub woofer). In my concept the system controller collects and processes the bit streams. Then the bit streams are sent (over firewire) to a small D/A located at the speaker. This eliminates expensive interconnect cables and any potential for signal modification over a long analog cable run. In my dreams this interface becomes popular enough that sub woofer manufacturers build in a firewire input and no adapter is required.

3. Multiple output streams. I sense multiple sub woofer systems growing in popularity. This system can support several sub woofers. That's also where time delay capability comes in. Each sub may need a different delay. Current audio processors only offer one delay for the LFE output. I saw a HSU Research demo with one mid bass module near field and two sub woofers in the corners that really pointed to a need for this capability.

Unfortunately I would not expect a USB to Firewire adapter to work. I'm unfamiliar with these devices, but I understand both protocols enough to know that would be very difficult. I expect a PCMCIA, expressCard, PCI, or PCIX card would be required for computers without a built in port.


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## Sonnie

I think the audio over Firewire is going to lose the interest of most... unless you plan to include Firewire cables and Firewire to XLR / Firewire to RCA adapters and/or the D/A unit. It's already enough that I suspect quite a few will have to buy some sort of adapter for Firewire use... which adds another $25 to the price... now for several we are at $275, which I think for the product to be successful, $199 is going the be the breaking point. And I can almost assure you, sub manufacturers are not going to implement Firewire into their subs as a result of this product and I would suspect it would be years before they would even consider it. It seems like it's getting way more complicated than it needs to be IMO. My suggestion would be to stick with XLR and RCA outputs to the sub... leave the Firewire for communicating with the computer.


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## Guest

This is the heart of what I need to know from this community.

It's not strategically valid for my company to develop this system unless it utilizes the full capabilities of firewire. Sorry, that's just the fact. To me, firewire to the PC is just a free benefit of the Firewire audio system backbone.

I don't think that is as bad as you imagine. I'd like to keep explaining till I'm sure you have a clear picture of my proposal. 

I'm still talking about a controller with analog inputs. No new cables there. We just have to decide what exactly the analog inputs are. Expansion to other more expensive inputs is purely optional.

The cables from the controller to the speaker can be Cat5 or possibly coax. Nothing expensive there. 

The D/A at the speaker might not even need a cable. If it did it would be very short.

One other advantage is that the speaker cables can be "chained'. Only one cable need come from the controller. The second speaker can be connected to the controller or the first speaker, whichever is easier. The third speaker the same. One firewire link can carry many audio streams. Each speaker adapter can figure out which stream to play.

I'm trying not to stray in to too many firewire details unless your interested. But there are many advantages to audio over firewire.

Here's the root question. If the cost were the same, would you prefer digital signal runs to the speakers or would you prefer analog runs? Personally digital runs make sense to me, but if that's not the current market feeling perhaps I'm ahead of my time.

I'd like to send digital signals to all the speakers. The sub woofer is the best place to start, because they almost always have built in amplifiers.

It seems to me you've crossed a bridge when you digitize a signal and filter it. Once you've digitized it you might as well take full advantage of the digital domain.

It looks to me the video guys are ahead on this issue. HDMI seems much preferred in the market to analog component video interconnects.

I'm happy to dig into this further if you have additional questions or worries. As I say, this is the most important issue to me in this discussion. Clearly I'm on a mission, but I've no desire to build a system no one wants.

Barry


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## Sonnie

I just don't think Firewire from the unit to the sub or sub amp is gonna fly. 100% of the subwoofers on the market today have analog inputs, 0% have digital inputs that I know of... you are going to introduce a product that in order to be functional, will immediately require a D/A converter and I don't see that being cheap if it's done right.

I don't see it working like you want it to. I don't know, maybe I'm missing something... maybe some others can chime in again with their thoughts.


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## Guest

Thanks for hanging in there with me and not just giving up. I appreciate it.

Here is my point on A/D - D/A. All digital parametric equalizer systems all require an A/D and a D/A. My proposal is no different. For a given quality level my A/Ds and D/As cost about the same as other solutions. The only difference is where the D/A is located. I propose locating it near the speaker to gain the quality and cost advantages of digital signal transmission over analog signal transmission. 

I don't think it would cost much more. It would cost less than analog Monster Cable and would be higher quality. (I know many solutions are better and less expensive than Monster Cable. )

If you liked this system but really wanted to run analog to the speakers, you could locate the D/A modules near your rack and run analog signals. No skin off my back. Nothing says the digital interconnect needs to be long, it just can be if you want. 

I'm guessing you still might have other issues regarding this type system. Or I could still be missing your point. Please help me out. Understanding these issues can either improve my proposal or help me avoid a huge mistake.:R


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## Otto

Would the D/A be included as part of your device? i.e., a separate box, but still a complete solution? If we have to buy a separate D/A it's more confusing. If you sell a complete solution, including the "main" box, a cable of whatever length, and the D/A box, that might be more appealing. We can then make or buy a longer/shorter cable as desired.


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## Sonnie

I'm not up for more boxes... I have enough now. I prefer a one box solution. I could be wrong, but I think most people will want a one box solution... that was our initial goal. I'm still not sold on Firewire from the unit to the sub and I don't think it will sell very well... sorry.... :huh:


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## Guest

Yes the intention is to supply a complete solution to integrate into todays analog world.

Sorry I wasn't clear on that.

I got off track discussing optional D/As or A/Ds that could be attached to the system if the standard I/O wasn't up to the requirements of the highest end customers.

I am considering a prototype that would rely on a separate, currently available D/A A/D box. It would be faster to get the platform going for software development without worrying about the analog bits up front. I doubt that prototype system would be available commercially.


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## Guest

Sonnie,

I appreciate fewer boxes. My concept for the D/A is a mouse sized box that could literally hang of the RCA or XLR connector to the sub amp, not another rack sized piece of equipment.

Can you expand on your concerns about firewire to the sub?


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## Otto

bvwj said:


> I got off track discussing optional D/As or A/Ds that could be attached to the system if the standard I/O wasn't up to the requirements of the highest end customers.


So would the "main" box have an analog output (preferably balanced). And then also a firewire output for those that wish to use an external DAC?


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## Sonnie

bvwj said:


> Sonnie,
> 
> I appreciate fewer boxes. My concept for the D/A is a mouse sized box that could literally hang of the RCA or XLR connector to the sub amp, not another rack sized piece of equipment.
> 
> Can you expand on your concerns about firewire to the sub?


The extra box is my concern... if it's small enough, then maybe it will work okay, but I didn't think DAC done right was cheap... is this not a concern? I've always heard of DACs costing at least a few hundred dollars... has it gotten that inexpensive now?

It's got to convert back to analog anyway, what is the benefit of it going an extra meter to the sub in the digital domain? Seems like to me the easiest solution is to put the DAC in the unit/box and let us use our analog cables out to the sub.


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## Guest

I agree, the DAC box at the speaker must be small to be a workable solution.

DAC's run from cheap to very expensive. The currently available $125 equalizers have 2 ADCs and 2 DACs inside, so they don't necessarily have to be expensive. The ones on the available equalizer also have to respond up to 20kHz. A dedicated sub DAC could focus on higher quality at lower frequency and possibly end up even less expensive.

It does all go back to analog. For 1 meter the benefit is small. In my theater, the run is closer to 10 meters and goes past or runs along with power lines, video cables, and other analog speaker cables. That's a lot to expect from an unbalanced line level signal. I would much prefer a digital interconnect. 

Ground loops of which I'm sure you have experienced are another analog issue that is quickly forgotten after moving to DC isolated digital interconnects.

I'm working on a modular approach for the main system unit. It is possible that an analog output could be added to the main unit. (You're wearing me down )

Is anyone but me attracted to the benefits of "digital to the speaker"?


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## Guest

I thought I would jump in here...

I like the idea of digital to the speaker. If I sit on the side of the room with the my current analog sub cable, my Blackberry phone induces a loud digital sounding buzz. 

The new processor sounds like a great idea to me. Adding basic RTA/Mic preamp functionality if it doesn't add to the cost would give non REW folks a chance to get their systems tuned fairly well with just the puchase of a mic and cable. 

Several studio monitor companies use a built-in RTA/filter bank (Genelec and JBL come to mind) to flatten the response of their speakers. Your proposed system could put flat sub response in the reach of non-tech types if it had an automatic self-adusting mode.

Take this for what it is worth- I'm just throwing out ideas here.

Thanks for looking at bass management!


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## blekenbleu

bvwj said:


> In my theater, the run is closer to 10 meters and goes past or runs along with power lines, video cables, and other analog speaker cables. That's a lot to expect from an unbalanced line level signal. I would much prefer a digital interconnect.
> 
> Ground loops of which I'm sure you have experienced are another analog issue that is quickly forgotten after moving to DC isolated digital interconnects.
> 
> I'm working on a modular approach for the main system unit. It is possible that an analog output could be added to the main unit. (You're wearing me down )
> 
> Is anyone but me attracted to the benefits of "digital to the speaker"?


I'm interested, but prefer optical; don't need any more stinkin' RFI.
DC isolation is huge for me, but then presumably need batteries or wall warts for DAC dongles..
It would be neat to automagically adjust phases, delays, levels and frequency responses based on PC software
that sorts out which of daisy-chained dongle-attached subs are best positioned to accommodate various room modes.


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## DrWho

I'm vote adamently against putting a dac at the subwoofer end of the wire. It's completely pointless and prone to all sorts of other issues. You do realize that you're going to need to send a DC voltage down the line to power the output stage of the DAC right?


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## Guest

Optical interconnect is a possibility, there exist optical solutions for 1394. It would be more expensive thus probably an option if sufficient demand develops. 

The 1394 signal is differential, kind of balanced, so it doesn't emit much EMI. It's also scrambled to avoid harmonic re-enforcement, and doesn't allow long runs of highs or lows. The signaling frequency is 62.5, 125, 250, or 500 Mhz. Well above anything in the audio bands.

The point of putting the DAC at the end of the wire is eliminating analog interconnect issues. Perhaps you have seen vendors trying to solve this issue with $500+ cables, spent a day killing a ground loop hum, or picked up noise from a halogen lamp dimmer.

I don't think I would run DC across the digital interface. You can run AC across cat5, but its complicated (expensive). I'm proposing an AC to DC converter at the DAC. The sub amp needs AC, so I would expect it to exist in the vicinity.

I don't get the analog devotion, perhaps you can help me understand. If you're a vinyl or tape lover more power to you, but most of us in home theater are left with audio entering our systems from DVDs, MPEG2, or MPEG4 digital streams.

So there you are. For my purposes it all starts digital. On the other end, it's becoming more and more digital all the time. Class D amplifiers may not be audiophile yet, but they are getting better and they require a digital input. The BASH amplifier in my Sub woofer is already half digital. 

A signal can't be improved with a D/A or an A/D so the fewer the better. An analog signal can only get worse running down a long cable, it can't be improved. The shorter the analog cables the better. A proper digital signal is the same at the end of a 1' cable as it is at the end of a 300' cable. 

If a D/A is necessary, and today it is, it can provide the highest quality closest to the destination.

There are frequently holes in my reasoning, feel free to point them out. I'm starting to think that because current parametric equalizers have analog ins and outs, it's been easy to ignore the fact that they contain 2 ADCs and 2 DACs. Since the current system costs <$150 it becomes obvious that they probably aren't audiophile ADCs and DACs. Now that I'm proposing separating them from the main unit, there is a little more daylight shed on the issue and people are demanding higher quality DACs. That could definitely be a perceptual problem with my concept. (Or an opportunity.)

Thanks again for all the input.

Barry


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## Sonnie

I don't really understand DACs, but it sounds like you are saying that we will have to power up the DAC at the end of the cable run to the sub... meaning this unit will require two AC outlets? I think this is going to be a drawback.

In situations like mine, I use a split output to my two subs from the 1124P. One is about 4' in length and the other is about 9'. Do they make a Firewire that will Y-split into two? Then I have to have 3 available AC outlets, actually 4 because I'm about to add a third sub. :dizzy:


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## DrWho

> The point of putting the DAC at the end of the wire is eliminating analog interconnect issues.


What specifically are these interconnect issues? You first have to identify the problem before offering a solution...especially a "solution" that is going to introduce other problems.

For what it's worth, you're not going to revolutionize the entire audio industry with this product. If you want to make money, then perhaps you should operate within the existing framework and tailor to the target market? Everyone here is already running an analog connection between their receiver and subwoofer without issue. There is absolutely no need to "fix" a problem that doesn't exist.

For what it's worth, it has absolutely nothing to do with a devotion to analog - quite the contrary actually.



> Since the current system costs <$150 it becomes obvious that they probably aren't audiophile ADCs and DACs.


Audiophile? If our source material is going through the same devices in the studio, then surely it must be good enough for playback at home. Semi-conductor based chips have also dramatically gone down in price as the manufacturing process has improved. A $50 transistor 15 years ago is now only costing $0.50...price really shouldn't be a determination of quality.

What ever happened to the notion of objective data? You know, actually measuring the performance of the various stages? The overall quality of a device certainly isn't going to be determined by the DACs alone...****, isn't the reason we're all here because we realize the benefits of objective data as it pertains to tweaking the sound of our systems?


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## LightwaveDude

My $.02:

The issue over firewire vs. USB isn't a big deal to me. If you want firewire for your product, go with it. While USB would be nice, I can see where you don't want to develop it for your product. ****, for my 1124P, I'm going to need to buy a USB to midi or a midi controller card to hook it up to my computer, so I don't see why a firewire card would be so bad (especially considering how much more useful firewire is than a midi card). So go with the firewire.

On the issue of the digital signal to the subs: I think it's a good goal and it sounds great in theory, but I don't see it working in the near future. I see the advantages, but I also have to look at my system, and I just see it being easier to use what I have which is analog RCA. If you really want to add your digital output to a D/A box by the sub, here's my suggestion:

Make the D/A box much like an iPod with a bay station. Make it small and give it a port or a cavity to plug into on the back of the unit which gives people like me, who want to keep everything in a stereo cabinet or rack, the ability to leave it all there and just run the signal a foot to an amplifier nearby. (I have a passive sub and so the distance to the sub is run by the actual power conducting speaker wire). Then, if you want to run a digital signal to your powered sub digitally as you suggest, unplug the D/A box from the back of the unit and run a signal wire to the sub.

The biggest problem I see with this is it requires custom chassis with a cavity for the D/A unit to slide into, which I can foresee increasing the price slightly (to what degree, I don't know).

This I see as a compromise between those of us who want the analog RCA outputs on the unit itself (without extra boxes in a sense) and the people who want the D/A located close to the subwoofer.

Edit: spelling and grammar


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## Guest

Sonnie,

It sounds like your system is my target market. If I can't convince you I might not have a market!

Yes, requiring more AC outlets is a downside. If the other upsides can't overcome that downside then I have a problem. In my system it would be simple to add a "power splitter" at the power input to my sub to provide the extra outlet. I understand everyone's implementation is different.

You can't normally split a FireWire (or USB, or Ethernet) signal. You can use a hub to offer more outlets. You can "daisy chain" firewire, that means running a single cable from one point to the next. Each FireWire device can also be a hub.

On the upside, I think independent three channel time delay, phase adjustment, and crossover would be ideal for a 3 sub system. Just splitting the same signal to three subs doesn't seem to maximize the potential of a 3 sub woofer system. A single firewire cable can carry dozens of audio streams. The DAC at the speaker just has to be smart enough to pick out the correct one.

I know it would be crazy for an unknown company to try to move the home theater audio market to digital interconnect. Fortunately, that's not what I'm trying to do. I expect that transition to take place by itself. I think digital to the speaker is inevitable. It took decades for sources to become digital. It took years for it to happen between the source player and the receiver. It will take less time for it to spread to the speaker.

I just want the transition to use my technology. I'm not alone. HANA (the High Definition Audio Video Network Alliance) demonstrated a FireWire sub woofer at the last CES. HANA is led by Samsung, JVC, Mitsubishi, Texas Instruments and others.

I'd like to develop and market a product that fits into today's systems that demonstrates and paves the technology path to future systems.

That's what I'm up to. But I still might be crazy.

Barry


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## Sonnie

Well, you see what myself and others are saying. Personally I think we are after something different than what you can offer, unless you are willing to reconsider your design. If you can get away from this digital to sub idea and just stick with Firewire for computer connectivity, then your product will be much more appealing. I just don't know what else to tell ya. :huh:


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## Guest

I was looking at unrelated stuff this evening and came across another potential solution.

Please evaluate this piece of equipment

I would like to know what you think of its analog I/O capabilities (levels, quality). I'm guessing it's very similar to the BFD I/O. These units can be had for $70-100.

Now, if I were able to offer a firewire DSP unit that used this for analog I/O for $100-150 and performed the processing we've discussed would anyone be interested?

I could probably even come up with a 17" case with room for the FCA202 in a slot in the back. If you wanted digital closer to the sub, you could use an additional FCA202 up to 4.5m from the first (no wall wart required). 

If you wanted more than 2 ins or 2 outs you could add another FCA202.

If this were popular, we could start designing lower cost single purpose DAC and ADC modules.

Am I getting closer?


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## Otto

So you're proposing to use that as the ADC and the DAC, right? I think it could work...


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## Guest

Yes, stage one would rely on the ADCs and the DACs in the FCA202.

That leaves us with only digital and mechanical issues to get to a useable system.


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## Guest

The design ideas have been wide ranging so I wanted to take updated stab at describing my current concept based on your inputs.

I've tried to attach a sketch below. If it works it will show:

a single unit with space to house the FCA202
ir input
led indications
firewire setup interface
single ac power cord
analog inputs (to FCA202)
analog outputs (from FCA202)

The FCA2002 interfaces to the DSP engine with a single FireWire cable. Audio in, audio out, and power are all supported with the single cable.

It seems to me this is close to what you've been asking for, while still being on my road map.

Anyone else still interested?


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## Otto

bvwj said:


> Anyone else still interested?


I am! I think it's on the right track for everyone. :T


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## Sonnie

Yeah... I think we could be getting somewhere. 

I'd like to see the full compliment of specs/features though... and maybe what the front will look like, rough draft so to speak.


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## otmopo3ok

Hello everyone,
Barry I appreciate your effort in pushing this R&D forward.
I'm very much interested in this kind of experiment. I'm all for digital-all-the-way but as of right now it seems running Firewire to each speaker is a bit pointless. Plus the argument of 'signal cable issues' doesn't apply to me since i run all my signal cables as short as possible and my subs are passive. (i never understood who invented running 30ft signal cables to subs when you might as well run 30ft speaker cable and avoid so much headache).

Since we can add another external Firewire in/out box will the DSP handle extra channels? 
If this is the case how many more channels can i add? (How powerful is DSP?)
Can some of them be full range?
All this needs to be updated through the software which hopefully will be supported and developed/expanded to include more channels and features?
If the answer is NO to all those above it means i have to buy another set of these boxes for couple more channels - which becomes much more expensive than going the PC route described below.

(My ideal system would be a noiseless-signal-PC (or powerful DSP chip) which will be doing all the DSP for 7.3 system through an external sound card with 10in/10out which would also do real time Room Correction. A DIY alternative to the one TacT is selling for $9,900. :raped: )
http://www.tactlab.com/Products/TCS/TactTheater7_3.html

But your system is a start towards that goal.


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## brucek

> Anyone else still interested?





> I am! I think it's on the right track for everyone


Well, maybe not everyone. 

I don't like to be negative about this, because I appreciate the effort that's been put into the proposal. I wonder how popular a device would be that required the addition of another companies hardware to operate?

The specs don't appear to be very good on the FCA202. Here's a few observations.

1. The analog output is _consumer level_ of +2dBV. This voltage is unsuitable for driving many PRO amps. 

2. The analog input has no balanced capabilities. Not acceptable to those using processors with balanced connections. 

3. They've weighted the S/N ratio and defined it at 1KHz. Typical trick to hide a poor noise figure. 

4. The harmonic distortion is defined at nominal levels and not max input. And why not total harmonic distortion so we know that more than the first order harmonics are considered. 

5. It has no gain control.

6. What are the possibilities of Behringer discontinuing this device , rendering the proposed equalizer unusable.

Anyway, I've just read through this whole thread and wonder if I'm the only one who feels the original intent of this project has left the tracks somewhat?

The basic premise was that we liked the BFD and _all its features_, but wanted to add on RCA connectors, provide better specs (like a 2496), extend the filter control down to 10Hz, maybe add a shelf filter, and clean up a few problems such as turn on thump and ground loop hum. Not a big deal for Behringer that already had devices that possessed these added goodies, and since the parametric feature was basically a cursory function in a feedback destroyer, we simply wanted everything removed except the parametrics with the addition of a few extras. Well within the purview of Behringer.

Again, for myself, the features that the BFD already offered _weren't on the negotiating table_. These were a given. That includes analog unbalanced and balanced XLR connections on both input and output, selectable input/output control between pro and consumer levels, a fully functional front panel with VU meters and filter indicators, etc, etc.... well, you get the idea, it's all in the list. I'm personally not interested in adding extra boxes on to get these basic features that I already enjoy, nor do I want to be adding firewire interface cards to my old REW computer. I have to be honest, and with respect, I never really warmed up to firewire, and when Apple dropped their support of firewire to ipods etc, well I thought the handwriting was on the wall. The device would have to support USB. I suspect that's somewhat of a global sentiment at this site, although I may be wrong.

Anyway, I know I'm only representing one opinion, but I'm not really interested in _convincing_ anyone about the basic features I require in a parametric equalizer. I already enjoy about 95% of everything I need in a cheap BFD. The project appears to have moved away from the basic needs to more of an attempt to showcase firewire than in providing what the market wants. That's fine, and I understand the business requirement, but I don't think the proposals so far would be a seller. That may well be evidenced in the lack of enthusiasm shown so far in this thread, with very few participants in relation to the numbers who voted in the BFD poll.

I'm no doubt wrong in my assessment of this device, and it would be the greatest thing since sliced bread. So feel free to ignore my thoughts....

brucek


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## Otto

Good points, brucek. I guess I could say I'm torn about it. On the one hand, I'm eager to have a better solution (10Hz, remote control, whatever turns you on...). On the other hand, we may be headed down a more complicated path. 

And I agree that the current basics of the BFD should remain -- why take a step back? I also agree that we get 95% of what we need for well under $100 on eBay.

Thanks for the comments.


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## Sonnie

I just needed someone to wake me up... thanks brucek! 

We need to get back to finding someone who can build what we really need.


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## Ayreonaut

Most of our current bass management signal chains include:

1. Digital Signal Processing (DBM) in the Reciever
2. D/A conversion in the Reciever
3. A/D conversion in the BFD
4. Digital Signal Processing (EQ) in the BFD
5. D/A conversion in the BFD

My receiver (and many others) has a digital optical output. It simply reproduces whatever digital in is selected. If you build a system that includes DBM and digital optical input (and coax, etc.) you eliminate 3/5 of the processing and souces of noise. The chain is then:

1. Digital Signal Processing (DBM and EQ) in the "Unit"
2. D/A conversion in the "Unit"

Shouldn't we insist on digital in?


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## brucek

> My receiver (and many others) has a digital optical output


The only function of a digital output on a receiver or processor is for digital dubbing using a CD or MD recorder. It's analogous to an analog _tape loop_, only in digital.

Conventionally, the receiver or processor do all the bass management and processing of the various digital formats (that require licensing) and then output analog to an external amplifier or speakers.

brucek


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## Ayreonaut

Ah. I guess you would have to have a full-fledged surround processor in the "unit" to construct the sub signal. Too much. :dumbcrazy:


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## Guest

> The specs don't appear to be very good on the FCA202. Here's a few observations.
> 
> 1. The analog output is consumer level of +2dBV. This voltage is unsuitable for driving many PRO amps.
> 
> 2. The analog input has no balanced capabilities. Not acceptable to those using processors with balanced connections.
> 
> 3. They've weighted the S/N ratio and defined it at 1KHz. Typical trick to hide a poor noise figure.
> 
> 4. The harmonic distortion is defined at nominal levels and not max input. And why not total harmonic distortion so we know that more than the first order harmonics are considered.


This is the input I wanted on the FCA202. 


> 6. What are the possibilities of Behringer discontinuing this device , rendering the proposed equalizer unusable.


The intent isn't to build a system around the FCA202. It's just a proposed starting place. The price point of the FCA202 almost enables a system at your price goals. There are several other higher quality (more expensive) FireWire ADC/DAC units. On the FireWire side they interface the same, so it would not be much effort to enable a number of different interface devices.

I envision smaller, much less expensive, single purpose devices (instead of 2x2, 4x4, and 6x6 units). I was just hoping the FCA202 might be a starting point to enable the system without investing immediately in analog I/O development.



> Anyway, I've just read through this whole thread and wonder if I'm the only one who feels the original intent of this project has left the tracks somewhat?
> 
> The basic premise was that we liked the BFD and all its features, but wanted to add on RCA connectors, provide better specs (like a 2496), extend the filter control down to 10Hz, maybe add a shelf filter, and clean up a few problems such as turn on thump and ground loop hum. Not a big deal for Behringer that already had devices that possessed these added goodies, and since the parametric feature was basically a cursory function in a feedback destroyer, we simply wanted everything removed except the parametrics with the addition of a few extras. Well within the purview of Behringer.
> 
> Again, for myself, the features that the BFD already offered weren't on the negotiating table. These were a given. That includes analog unbalanced and balanced XLR connections on both input and output, selectable input/output control between pro and consumer levels, a fully functional front panel with VU meters and filter indicators, etc, etc.... well, you get the idea, it's all in the list.
> 
> I'm personally not interested in adding extra boxes on to get these basic features that I already enjoy, nor do I want to be adding firewire interface cards to my old REW computer.


I certainly can't demand that you negotiate features with me. I just thought I spotted an opportunity that might fit me better than it fits Beheringer. I'm really not trying to negotiate as much as I'm trying to understand what the critical features are. Clearly some features of existing systems are required and others are not. I have my opinions, but I appreciate yours.



> I have to be honest, and with respect, I never really warmed up to firewire, and when Apple dropped their support of firewire to ipods etc, well I thought the handwriting was on the wall. The device would have to support USB. I suspect that's somewhat of a global sentiment at this site, although I may be wrong.


Apple dropped FireWire support on iPods, there really isn't any etc. All the new Macs have firewire. It would be much more difficult and expensive to develop this sort of device with USB. 



> Anyway, I know I'm only representing one opinion, but I'm not really interested in convincing anyone about the basic features I require in a parametric equalizer. I already enjoy about 95% of everything I need in a cheap BFD. The project appears to have moved away from the basic needs to more of an attempt to showcase firewire than in providing what the market wants. That's fine, and I understand the business requirement, but I don't think the proposals so far would be a seller. That may well be evidenced in the lack of enthusiasm shown so far in this thread, with very few participants in relation to the numbers who voted in the BFD poll.
> 
> I'm no doubt wrong in my assessment of this device, and it would be the greatest thing since sliced bread. So feel free to ignore my thoughts....


There is no way you can be wrong on this. Obviously you understand exactly what you want. I just keep poking you with sticks looking for sore spots any you've been kind enough to tell me how bad it hurts.

I appreciate that you don't dismiss my business requirements. My goal is to showcase FireWire AND provide what the market wants. You're accurate that I understand FireWire better than the market. I'm participating here to learn about the market. 

I will continue to appreciate any effort you choose to spend convincing me of the basic features you require in a parametric equalizer. I can't promise a device that delivers your exact feature set, but I am listening.


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## ACGREEN

I agree that in a perfect world, that audio signals would be fed to the speaker in a digital format with the speaker being amplified with its own DAC. With most receivers converting every signal to digital the signals would only have to be converted once and remain in the noise-free digital domain. 

The problem. Speakers would require power. This would be a difficult transition in a set market. 

With you device, I think to mush analog-to-digital-to-analog processing is going on. I think that more noise would be introduced then would be saved my the digital runs. 

While I would love a subwoofer calibrator for under $200, I don't think Firewire is the answer. 

I am trying to think of some applications for firewire...


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## Danny

I like the idea of digital to the speakers however the supply of power to the device presents a problem that needs to be solved (perhaps a IEC in and also an output IEC connector, that is power going into the device powering it and then going to the sub). I would like the idea of having PC control of the device (maybe like Sabine have done with their GraphiQ range)


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## Danny

And also maybe you could investigate the idea of making the unit full range compatible and include a graphic EQ. This would increase the viability for pro audio to use it. Currently in many installations there are long 100ft plus analog cable runs from the desk to amps rack. There has been an increased occurrence of digital products as well eg Roland Digital snake.


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## Fader

bvwj said:


> Sonnie,
> 
> I appreciate fewer boxes. My concept for the D/A is a mouse sized box that could literally hang of the RCA or XLR connector to the sub amp, not another rack sized piece of equipment.
> 
> Can you expand on your concerns about firewire to the sub?


I assume that in this concept, you would need one of these mouse sized D/A at each sub? What would be the add on cost for each additional D/A?


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## Guest

My target for a single channel, unbalanced, sub D/A is $40-50, so $50 for each additional sub. Blanced might be a little more. Full range might be a little more. Two channels might be a little more. If I could convice a sub manufacturer to integrate it, a digital-in sub could be less expensive than a similar analog-in sub.

Under 15' (4.5m) power is easy. Standard FireWire cables can carry plenty of power to power all the DACs. No external power supply is needed. In addition, the speakers can be chained from one to the next, so each speaker does not need its own cable run to the equipment rack. For $20 you could extend the run to 30' with a cable powered hub (repeater/splitter). Additional repeaters would be functional, but seem like a poor solution.

For longer distances (up to 100m) you would want FireWire over cat5 or coax. It's more expensive to send power over these cables, but it is possible. Currently I'm thinking it would be most economical to use a wall wart at the end of cat5 and coax runs. Then other DACs within 15' of the long run could again be cable powered.

There is nothing in the DSP archetecture that limits this system to low frequencies. The current concept is sub woofer based because that's where the largest audible gains can be made and because currently that's where the powered speakers are.

The market is beginning to understand digital interconnect. I like this digital snake from I/One. Of course it's FireWire. The entire system can cost less than some multi-channel analog snakes.

Historically audio manufacturers saw FireWire as an interconnect to get audio data into and out of PC's. New extensions to the FireWire standards make it ideal for distributing audio data as well.


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## Guest

If you can satisfy the basic requirements of this group (current BFD features plus wanted improvements), and have this feature: "included filtering and SPL meter capabilities", I'd be interested and would cancel my plans to buy the Galaxy 150 and accessory software.


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## Guest

Don't wait on me if you're ready to do something now. I'm only in the concept / prototype stage. I haven't made any commitments for features or dates.


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## ACGREEN

Have you thought about audio/video distribution for new homes. This might be better suited for using the application you desire. I am building a new home and the most economical system I can find is Audio Authorities system which runs over Cat5. Maybe your technology would be better suited?


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## Guest

Barry, thanks for your forthright post. I'm in no hurry and there's a Tuesday deadline for the Galaxy buy, so given that I've got an old RS meter and a recently purchased Behringer ECM8000 microphone and a friend with lots of gear and software and my newTrueRTA and the software on this forum that I plan to learn and use, the ultimate hardware solution, whether your company's or another's can wait.

Also consider ACGREEN's comments. My good friend is having a house built and I am very concerned at what he's paying for wiring his new home for phone, TV, computer, audio, etc. Not that the subcontractor is ripping him off, because I know the number of wires, CAT5, COAX, etc and the associated labor hours involved. Is the alternative a daisy chain single (or almost single) run of firewire??


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## mojave

brucek said:


> The only function of a digital output on a receiver or processor is for digital dubbing using a CD or MD recorder. It's analogous to an analog _tape loop_, only in digital.
> 
> Conventionally, the receiver or processor do all the bass management and processing of the various digital formats (that require licensing) and then output analog to an external amplifier or speakers.





Ayreonaut said:


> Ah. I guess you would have to have a full-fledged surround processor in the "unit" to construct the sub signal. Too much.


I plan to us a simultaneous analog and digital output with my X-Fi Elite soundcard. It will decode the surround modes and send it out via analog. It will also combine the decoded signal into a stereo pcm digital s/pdif signal. I connect the analog outs directly to my 7 channel amplifier. I will connect the stereo digital coaxial out to a Behringer DCX2496. I will then split the signal to three outputs for my subwoofer, mid-bass module, and Buttkickers. The DCX2496 will handle the crossovers, parametric equalization, phase adjustment, and delay before performing the D/A conversion. I can also control all settings from my computer using Behringer's software.

I received the DCX2496 last week, but I am still waiting on all the cables to arrive before I set everything up. If this works as planned, I will have eliminated a D/A and A/D conversion step.


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## ToSi

Barry,

I think that to really convince users here to switch to your new system, you'll need to offer features that aren't available in the current commercial products or market to a user base who's needs aren't being met w/ the current offerings.. 

ACGREEN's suggestion has merit, although I wonder if the cost penalty of using Firewire vs. CAT5 is going to make it possible.

Another option would be to look at the DIY speaker community. Dipoles & active speakers are growing in popularity in the DIY community & there is a lack of affordable digital solutions that can apply the signal corrections necessary to implement these. 

Take a look at the active filters page on the Linkwitz Lab site (http://linkwitzlab.com/filters.htm) - I'd be particularly interested in an affordable solution that could apply various combinations of these filters to a signal & output to respective amplifier channels. You could offer modules that handle 2 / 4 / or 6 channels, then rely on the IEE1394 backbone to link additional units together. A/D or D/A can be separate modules. Combined w/ a parametric EQ, these would provide the original features you were hoping to implement (room / bass management) + offer something new that would provide product differentiation. 

A separate issue would be to increase the usage of IEE1394 in consumer a/v gear but that's something you'd want to push the equipment manufacturers to do. As an interim solution, you'd want to offer a D/D module that makes it possible to maintain a digital connection to downstream components that don't use firewire. A similar device should be provided to convert SPDIF / Toslink / AES to IEE1394 upstream of your modules.


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## Guest

Wiring:

Audio/Video distribution for new (and old) homes is the point.

I believe FireWire has the most compelling advantages for the home AV network. It's not just me, it's also HANA. You'll see many of the major consumer electronics companies are participating in HANA.

I won't explain all the advantages here. TI just authored an article on why 1394 was the best choice for the future home AV and data network. 

I think this is coming. My idea is to come to the market ahead of the curve and carve out my piece.

One of the major recent developments in FireWire that enables home AV backbones are the new long haul physical interfaces. FireWire devices can now be implemented to run over standard Cat5 cable up to 100m. The ability to run FireWire over coax is in work and should be available shortly. 

The focus of this development has been to enable FireWire AV networks over existing in home Cat5 and coax wiring. The FireWire chips enable both star and daisy chain topologies. Loops are even allowed 1394b enabling redundancy if one segment of the loop breaks.

One wire from any AV component to the next has always been a major feature of FireWire.


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## Guest

Note ToSi's input - another product possibility for the DIY and CEDIA installation market. If powered speakers are in the future, then doing a product for DIY'ers to enable dipole and active speakers now will get your name in the market and get you ready for the bigger market segment. The new small, effecient class D amps could be deployed at the speakers.

Okay, so what is the most likely product?


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## Guest

The business case:

The impetus for this discussion was a request for a bass management system that improved on the currently available and affordable 90% solution. It's clear who would be the best manufacturer to produce that device. It appears they are not interested in this market.

In my view it would be foolish for another company to develop this improved BFD. If the product were successful it would be too easy for B to upgrade their device and thank you for the free market research while they undercut your price.

To be successful a new product has to have a new hook that offers some protection from this type of competition. I also think you have to "shoot ahead of the duck" and look for features that will be important in the near future.

My hook is the FireWire backbone. My emerging feature is digital to the speaker. I understand you can't sell a product in the present that's designed for the future, so I'm trying to understand the legacy requirements I need to support for a product that's attractive today and paves a path toward the future.

The other issue is that this development requires capital. So far this effort has no external funding. If someone wants or believes in this type of product enough to help fund development I would be far more willing to implement their suggestions.

The way it stands now it's my funding so the features need to make sense to me. I appreciate your efforts to convince me of your viewpoints. Many of your ideas have impacted my plans and challenged me to look for better solutions.

I should have a firmer product specification proposal to share shortly.


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## Guest

Barry,

Your business reasoning is spot on and you are thinking correctly. Yes, if you do an improved version of B's product, they would likley copy it and maybe tweak a feature in order to claim better than you. B is know for copying products.

Hang in there and come up with something with some IP content or a product for a niche market that wouldn't be of interest to a big B company today, but that could be expanded into that future market. The home infrastructure and active crossover implementations look interesting.


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## Guest

Processing:

I'm really not interested in analog processing. My only analog focus is impedance, level, and low pass to the A/D then the inverse for the D/A. I expect there is a contingent that loves the "op amp sound", but I don't think I can help them.

It seems to me if any part of your process is digital you've already lost the pure analog benefits, so you might as well take full advantage of the digital domain.

The good new is that all the analog filters that have been mentioned have digital counterparts. They can all be reproduced with 2nd order IIR filters. Here is an excellent introduction on how. 

I believe the digital filters offer the tweaker much more tuning and testing flexibility to try different filters without soldering down new components. My goal is to offer a digital processing platform that is simple to setup, but offers options friendly to advanced filter tweakers.

That's a fundamental advantage to the PC setup architecture. Filter software is relatively easy to setup and run on a PC. The results of this process can then be downloaded to the processing system and the DSP can do what it does best, run filters not design them. This allows upgradeable filter development via PC software updates rather than configuring a few preset algorithms to a standalone unit.

Implementing a leading edge general purpose DSP system was my initial concept for system processing. That provides ultimate flexibility, but also requires a lot of software development to make the system work at all.

Recently I stumbled on to a leading edge limited purpose DSP. It still has state of the art capabilities, but only requires register based setup to operate. The processing software is built in (and fully tested). This limits its capability, but I think its existing capabilities are very much what is required. I believe it can achieve 99% of what we need and can reduce development and time to market by half. It also cost less.

Please evaluate these capabilities.

3 independent processing channels -- Connected inputs can be unlimited (FireWire). Each of the three channels can be a mix of up to 6 inputs (8 physical inputs total). Each of the three outputs can be sent to unlimited destinations (FireWire). Each of the three channels has it's own independent processing capabilities (plus some interconnected capabilities).

16+ filters per channel -- Each filter is a 2nd order IIR biquad cascaded to the next (48 bit data, 28 bit coefficients). Each of these filters can be used for a parametric band filtering. They can also be used for crossover filters, phase adjustment, or any other IIR filter. There are a few more filters available for parallel summing, but they don't seem very flexible.

Delay buffer -- Each channel has adjustable delay before its output. There is also reverb delay summing but I doubt that adds much benefit for us.

VU meter -- Each channel can be processed through a VU meter and the results reported back to the system.

Soft mute / volume -- ability to avoid popping across setup changes.

Shelf filter -- I'm not sure how valuable this actually is, it's not completely parametric. There is a small selection of fixed frequencies and a large selection of gain / cut levels.

Dynamic range compression/expansion-- Again I doubt this adds value, but it's available. It allows pushing soft signals up or loud signals down a programmable amount. It's very parametric with dual range adjustable slopes and levels.

8kHz-96kHz sample rates. 24 and 32 bit samples.

The big thing that this DSP doesn't offer is FIR filtering. Possibly a future device could implement a general purpose DSP for FIR filters. The current system concept does include an FPGA which could offer some FIR capability, possibly an FIR sample rate converter for higher quality bass processing. 

Without including input, output, or user interface specific issues, does this processing capability sound adequate? I sure hope so, it looks like a sweet solution to me.


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## Guest

I think firewire is a great idea, but in describing it this way it seems to me that you are eliminating the s oundcard's DAC, or are passing a digital signal on to an outboard DAC. 

This is a terrific idea because it eliminates the noise and interference (and general poor quality of many PC sound sources)

I love the idea of balanced input with phantom power to use with my ECM 8000 that's great, as is the inbuilt SPL to calibrate the mic to a reference level.

The way you are describing this now, it sounds to me like a high quality outboard DAC/Preamp with parametric capabilities - It is almost a Zhalou DAC / Yulong Crystal DAC & Feedback Destroyer in one box - a killer combo? 

Is this the approach - I'd encourage a search / read on the Zhalou / Yulong - they've had terrific reviews.

That said the Zhalou/Yulong devices are high quality DACs, but they alone run in the $200 range to have a high quality audio path. They also include things like socketed opamps so that you can replace them with some of the newer chips that come out - I like the LM4562 and would encourage it's use, or at the least socketed op-amps to make it easier to mod. The LM4562's can be spendy and maybe only enthusiasts will want to take that approach.

So - is this a combo DAC / Parametric EQ? or would you use this as a pre stage going to an outboard DAC? Is it optimized for 2 channel or multi channel calibration? would you include a sub woofer pre-out on it?


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## Guest

I have to admit I'm surprised no one posted much enthusiasm for the capabilities of the audio processor I described.

It seems to me a near ideal way to get the functionality we've been discussing at a very reasonable cost.

One thought I have is that the description is a little abstract and a better description of the actual configuration might be more interesting.

To that end, I mocked up a configuration form prototype. Please click the link to have a look. The form doesn't actually do anything, it just illustrates the potential flexibility and ease of setup.

I'll quickly describe the blocks.

Across the top are selections to configure up to 10 seperate setups, plus the default (bypass) setup.

Up to 8 inputs can be selected from a very large number of potentially connected ADCs or digital streams.

Next these selected inputs can be mixed onto the 3 processing channels. Or a single input can be used 100% for the channel(s).

Each of the three channels can then be directed to a specific analog (or digital) output.

The center block configures the parametric filters for each of the three channels. Up to 10 filters can be configured for each channel. The center frequency as well as the bandwidth and gain are fully selectable. The PC will calculate the proper coefficients for the DSP. I didn't add all the configuration boxes for all the band filters, assume the table would expand as additional filters are activated.

On the right side are crossover configurations for each channel. 12 and 24 dB slope filters are selectable or bypass-able. Please note the phase at each crossover frequency is also configurable.

Delay is pretty self explanatory, I guess it could accept feet or meters instead of milliseconds.

I didn't put in shelf filtering capabilities, I'll have to think a little more on how to implement their interface.

Of course there can be options for more advanced users to enter their own coefficients, but I wanted to display here just how easy and powerful a simple configuration system could be. 

Again, this type of interface would appear on a FireWire connected PC during system setup. After setup, the user would just select one of the configured presets (without needing a PC).

Does that help describe the concept and capabilities?


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## Ayreonaut

Um, "easy" is not the word that comes to mind...


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## Sonnie

The main hang up I think most everyone has is Firewire to the sub amp and having to have some sort of powered DAC at each sub. I have three subs, two in each front corner and one in the rear of the room. 

I don't really have that big of a problem with Firewire from the computer to the unit itself, although I'll have to buy some sort of Firewire adapter for my laptop. 

The interface appears simplistic enough. The unit itself needs to have simple and current connectivity, not something we have to jump through 10 hoops to make work.


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## Guest

I like much about your approach of digital to the speaker as well as the ability to drive each speaker/driver locally.
While this may be a bit out of the topic - are you considering a unit that would do full range DRC and Speaker/driver correction?
Basically I am thinking of a systems that would use digital in and drive potentially each driver with a seperate amp and would function as the crossover in the digital realm doing phase/amplitude correction. This would be similar to Audyssey system but operate in digital to the speaker/driver.


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## Chrisbee

I keep wondering why anyone would want to reinvent the wheel and give it a fragile Firewire axle?

brucek said it all. The AV/HT world is now aching for a BFD without the trimmings and tidied up in detail. This is a real worldwide AV/HT need that nobody is listening to. Nobody! 

Rightly or wrongly we sell the idea of electronic subwoofer equalisation to everybody who will listen on the AV forums worldwide.

We simply want a BFD that can filter right down to 10Hz, has silent on off, doesn't hum and doesn't look like a cheap 70s scifi spaceship prop. 

Behringer's shortsightedness in removing the 1124P from the market without offering a real replacement is so stupid they should crash and burn! 

They were given a heads up by Sonnie but chose to ignore it because it probably wasn't in their "normal" pro-gear marketplace. They obviously haven't a clue about their customer base! Or couldn't care less about the hundreds of thousands of potential customers now looking at SMS1 and turning their noses up at the dumb price tag.

Thousands and thousands of 1124Ps were purchased by sub owners worldwide from any music store that had them. Sub owners loved them or hated them but they still learned to use them to make their subs listenable in perfectly ordinary domestic rooms. John M is a saint for producing REW! brucek and Sonnie should be honourably knighted for their work in making REW work for idiots like me.

Most sub owners don't want a computer in their AV room/HT except to set the sub up with REW + BFD and then forget it. 

Most sub owners don't want to spend more than a couple of hundred dollars making their sub's work as nature intended. That probably includes the SPL meter too! 

They want to use cables they recognise as cables. Balanced XLR and USB.

Offer us a tidied up BFD1124P and you will have to fight us off. Provided you make a 230 Volt 50Hz version for Europe etc.

I wouldn't buy your Firewire box with all the dangly bits if it cost pocket change and fitted in a matchbox. It doesn't interest me. It has no relevance in my AV world. A BFDi (improved) does interest me and I would pay twice what my trusty 1124P cost me without batting an eyelid. :T


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## khellandros66

I'd love to see someone develop this to handle up to 5-6 subs and independently measure and control them.

I will end up at some point with a projection system and CIH and have room to do 

3 x Definitive BP7006 for the front L/C/R and each tower has a 300w RMS 8in sub, plus room for two more LFE subs

EDIT:I hope and plan on doing Denon AVR3808 + Emotiva BPA-1 (3 for the 7006s) and would love to set the towers to small and use the "X" device to be a go between for LFE to the amps then to the towers LFE RCA input. Along with this two subs in rear or two small IB...

~Bobby


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## Guest

Pellicle said:


> I like much about your approach of digital to the speaker as well as the ability to drive each speaker/driver locally.
> While this may be a bit out of the topic - are you considering a unit that would do full range DRC and Speaker/driver correction?
> Basically I am thinking of a systems that would use digital in and drive potentially each driver with a seperate amp and would function as the crossover in the digital realm doing phase/amplitude correction. This would be similar to Audyssey system but operate in digital to the speaker/driver.


It sounds like you're talking about custom full range speakers. I think I can see how this sort of device would add value. 

Would that market require DACs or would they want to receive a standard IIS digital stream and build their own DACs? 

Is $150-$250 per 3 way speaker too much for a digital filtering and distribution system for the DIY speaker market?


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## Wayne A. Pflughaupt

bvwj said:


> Is $150-$250 per 3 way speaker too much for a digital filtering and distribution system for the DIY speaker market?


Seems a bit pricey for a mono unit. Not to mention, not sure how many DIYers will find the extra AD/DA processing attractive (sure wish some manufacturer would make a receiver or pre-pro with volume-controlled digital outputs). And once again, you’re competing with Behringer’s cheap _stereo_ crossovers...  They’re pretty popular on the home front.

Regards,
Wayne


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## Guest

I like Barry's ideas . 
I like Digital to the sub, specially over a 20ft run. 
I myself will be willing to pay $250, I am about to pay $250 for a Behringer FBQ2496 and it is not even supported in Canada anymore.
BTW will this be available here in Canada at this cost? are you all talking USD or CDN $$$.


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## rcarlton

Anything new on the idea front bvwj?


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## muzz

My belief is that MOST HT folks like/Prefer HDMI for 1 reason, and really only one reason..
Ease of use/hookup because of less cabling
Other than that, I don't see the benefit myself.


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## RayJr

Chrisbee said:


> I keep wondering why anyone would want to reinvent the wheel and give it a fragile Firewire axle?
> 
> brucek said it all. The AV/HT world is now aching for a BFD without the trimmings and tidied up in detail. This is a real worldwide AV/HT need that nobody is listening to. Nobody!
> 
> Rightly or wrongly we sell the idea of electronic subwoofer equalisation to everybody who will listen on the AV forums worldwide.
> 
> We simply want a BFD that can filter right down to 10Hz, has silent on off, doesn't hum and doesn't look like a cheap 70s scifi spaceship prop.
> 
> Behringer's shortsightedness in removing the 1124P from the market without offering a real replacement is so stupid they should crash and burn!
> 
> They were given a heads up by Sonnie but chose to ignore it because it probably wasn't in their "normal" pro-gear marketplace. They obviously haven't a clue about their customer base! Or couldn't care less about the hundreds of thousands of potential customers now looking at SMS1 and turning their noses up at the dumb price tag.
> 
> Thousands and thousands of 1124Ps were purchased by sub owners worldwide from any music store that had them. Sub owners loved them or hated them but they still learned to use them to make their subs listenable in perfectly ordinary domestic rooms. John M is a saint for producing REW! brucek and Sonnie should be honourably knighted for their work in making REW work for idiots like me.
> 
> Most sub owners don't want a computer in their AV room/HT except to set the sub up with REW + BFD and then forget it.
> 
> Most sub owners don't want to spend more than a couple of hundred dollars making their sub's work as nature intended. That probably includes the SPL meter too!
> 
> They want to use cables they recognise as cables. Balanced XLR and USB.
> 
> Offer us a tidied up BFD1124P and you will have to fight us off. Provided you make a 230 Volt 50Hz version for Europe etc.
> 
> I wouldn't buy your Firewire box with all the dangly bits if it cost pocket change and fitted in a matchbox. It doesn't interest me. It has no relevance in my AV world. A BFDi (improved) does interest me and I would pay twice what my trusty 1124P cost me without batting an eyelid. :T


I was reading this thread, and was going to make a comment....but this quote above did it way better then I could have. The BFD is a good product....remove all the button and lights, give it a USB port that I can use to dump filters that I create in REW, and a few memory banks for storage, and NO external adjustment ( so once it is set people don't fool with it ). If you are using a BFD....you are already using REW...so why does the unit have to have a mic and preamp built in. In my opion..less is more.

My .02
RayJr


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