# Active crossovers and speakers - amplification?



## Zeitgeist (Apr 4, 2009)

I've seen some interesting plans for 2-3 way speakers that use active crossovers.. By active crossovers, I mean Behringer DCX2496 or some of the cheaper models.

However, with active crossovers and separate line level outputs - with a pair of 3 way speakers, you're looking at having 6 sources to amplify. What do most DIY builders do - when they need to amplify 4-6 channels for a pair of speakers?

Multiple pairs of amps? Or a multichannel HT amp?

Or...... are active crossover arrangements that uncommon because of the issues with number of amp channels needed.


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## torceador (Sep 8, 2010)

Zeitgeist,

This method, called bi-amping (or tri-amping for three ways) has been around for a long time in commercial sound reinforement. It separates the frequency ranges prior to final amplification. This is different than a passive crossover in a cabinet, which takes a full-range signal and attempts to deal out frequencies to different drivers, and hopefully presents a relatively flat frequency response output.

Although it does add quite a bit of complexity, it has a few advantages....

1. You are not locked in to a fixed crossover and can change the frequency response of the signal driving each of the cabinets (you can't really change the response of a driver in a particular cabinet, just compensate for it)

2. You can use higher power amps for the low frequency stuff, and less powerful and perhaps better sounding ones for the mid to high frequency parts.

3. You don't lose power in passive crossovers 


Does it sound better? If you are going for LOUD it might be the way to go. Personally, I have let this particular technique go, in favor of reduced complexity.

torceador


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## Zeitgeist (Apr 4, 2009)

torceador said:


> Zeitgeist,
> 
> This method, called bi-amping (or tri-amping for three ways) has been around for a long time in commercial sound reinforement. It separates the frequency ranges prior to final amplification. This is different than a passive crossover in a cabinet, which takes a full-range signal and attempts to deal out frequencies to different drivers, and hopefully presents a relatively flat frequency response output.
> torceador


Hi Torceador, 

I've read about the advantages - and personally I like to tweak and play with things - so being able to change the crossover points and gains of each driver had some appeal to me..

I have an Onkyo PRSC886 - which supports biamping (which I'd like to do.....) - but I 'd lose 2 of the surround channels by biamping. It uses 2 of the surround channels for it. But I don't own bi-ampable speakers anyway. 

I was just curious if the practicality of needing to power 4-6 channels makes biamping/triamping unpopular.


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## Lucky7! (Jan 7, 2008)

Zeitgeist said:


> I've seen some interesting plans for 2-3 way speakers that use active crossovers.. By active crossovers, I mean Behringer DCX2496 or some of the cheaper models.
> 
> However, with active crossovers and separate line level outputs - with a pair of 3 way speakers, you're looking at having 6 sources to amplify. What do most DIY builders do - when they need to amplify 4-6 channels for a pair of speakers?
> 
> Multiple pairs of amps? Or a multichannel HT amp?


I use multiple amps.



Zeitgeist said:


> Or...... are active crossover arrangements that uncommon because of the issues with number of amp channels needed.


In terms of commercial designs, I feel active designs are less common for the simple reasons of most philes are used to passive designs plus it's much harder to mix and match amps and speakers, and in DIY for the added cost and/or complexity. DIYers seem to come in two basic performance flavours, bang for $ and push the performance envelope. The former will tend to go for passive, though for a 2 way, once a few xover components are purchased you aren't all that far from the cost of the active if you hunt around and buy secondhand amps at good prices.

I had my first active system 20 years ago and whilst I've built some passive designs since, the advantages of active, especially with the digital designs on offer are so great that I don't bother with passives at all, and can never see me going that way again. Designing passive xovers is a massive pain, even with xover software such as PCD and they don't have other features such as EQ and delay, let alone the ability to instantly change a setting to see how that sounds.

I don't understand the complexity argument at all. Once in situ and dialled in there is no need to touch anything except source selection and volume control, ie exactly the same as a passive system, The only time I could see it being a real issue is if you were extremely tight for space and even then there are work arounds.


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## Zeitgeist (Apr 4, 2009)

Hi A9X- Thanks for your comments...

I've seen a number of commercial arrangements that rely on active crossovers (most?) -- so interesting to see that it's so much less common in non-commercial environments.

But no doubt - there are a lot of reasons why commercial use active - from flexibility to high power..

Active crossovers and multiple amps has some appeal to me - in part because of passive crossover design. Seems like designing a good crossover is much harder than other aspects of speaker design.


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## Lucky7! (Jan 7, 2008)

Zeitgeist said:


> Hi A9X- Thanks for your comments...
> 
> I've seen a number of commercial arrangements that rely on active crossovers (most?) -- so interesting to see that it's so much less common in non-commercial environments.
> 
> But no doubt - there are a lot of reasons why commercial use active - from flexibility to high power..


Cheers. Undoubtedly the performance factors of flexibility and no power loss and stable performance with temperature (ambient and heated with use) of active over passive makes obvious engineering and commercial sense for large PA systems. Why apart from the reasons I mentioned this hasn't translated to home systems baffles me to some extent at least in the more expensive end of the scale. A set of Meridian or ATC speakers would only need a source and preamp to make a complete 2ch system of very high quality and WAF as it would have a low aesthetic footprint.



Zeitgeist said:


> Active crossovers and multiple amps has some appeal to me - in part because of passive crossover design. Seems like designing a good crossover is much harder than other aspects of speaker design.


Passive xovers are difficult to do and get right, plus can consume a lot of excess cost in redesign if parts are changed out. Plus no passive could ever begin to come close to what something like a DEQX could achieve.


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## Zeitgeist (Apr 4, 2009)

What are losses like.... % wise in terms of total power for a driver in passive crossovers?

10%? 30%?


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## Lucky7! (Jan 7, 2008)

In domestic use, except for LF xovers to subs or extremely inefficient speakers, not much. I doubt more than 1/2 dB, worst case outside of the exceptions.


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## coony63 (Sep 15, 2010)

If you are interested in active crossovesr check out minidsp prossesers very slick units.


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## Trick McKaha (Oct 7, 2009)

I'm using some active EQ and use an old Yamaha receiver as a multichannel power amp, in addition to an Emotiva XPA5 that powers the main speakers. I use a new Yamaha receiver as if it were a pre pro, not using its power section at all. For a middling diy er like me, active EQ is just easier to get right, and that makes home building speakers practical for me.


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## Zeitgeist (Apr 4, 2009)

Trick McKaha said:


> I'm using some active EQ and use an old Yamaha receiver as a multichannel power amp, in addition to an Emotiva XPA5 that powers the main speakers. I use a new Yamaha receiver as if it were a pre pro, not using its power section at all. For a middling diy er like me, active EQ is just easier to get right, and that makes home building speakers practical for me.


I'm actually going to go active........ and just have to invest the money in amps. I have a UPA7 that I'm using - and thinking about using it just for the tweeters for some 3ways that I'm building... I just wish you could adjust the gain of each channel on the UPA7.

I'm building some new 3 ways - and I need the flexibility that an active crossover provides - and the ability to adjust the gain on each channel.

Thanks for the comments from people..


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## Yad (Oct 19, 2009)

Active crossovers and per-driver amplification is the best possible way to built the speaker system. If you whant, i'll tell you why, but later: now i have to go.


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## lsiberian (Mar 24, 2009)

Yad said:


> Active crossovers and per-driver amplification is the best possible way to built the speaker system. If you whant, i'll tell you why, but later: now i have to go.


This is debatable. It certainly has it's advantages, but it also has its problems. Best is a subjective term that depends on the project requirements.


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## Yad (Oct 19, 2009)

lsiberian, i mean only objective quality characteristics of the sound-reproducting system: all kind of distortions, phase and time allingment, low group delay parameter, best possible step-responce, total control of all drivers and possibility to use amp-s with different output impedances (current source) for per driver (etc). 

Sure, it does not concerns a financial and a commercial sides of this question.


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## cast55 (Dec 30, 2010)

What are the disadvantages? The only one I can think of is the need for more amps, which can be tough for those with a limited budget.

I too, will never again build a passive system.


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## Zeitgeist (Apr 4, 2009)

cast55 said:


> What are the disadvantages? The only one I can think of is the need for more amps, which can be tough for those with a limited budget.
> 
> I too, will never again build a passive system.


Could noise floor somehow be a disadvantage?

More amps...... active crossover....... more cables? I don't know. Just throwing that out there.

A good amp is an amp..... but I imagine that the active crossover is the biggest part to either help or hurt.

I'm thinking about a DBX Driverack PA+ rather than a DCX2496..


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## SirKevi (Jan 31, 2009)

Active speakers offer many advantages over passive crossovers one downside is trying to keep the amps slew rate as close as possible read on linkwitz's site about active crossovers and amplification. The biggest advantage of active digital crossovers is that if you ever move the speakers or decide to up or downgrade you can continually modify you crossovers at no additional cost.


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## Zeitgeist (Apr 4, 2009)

It looks like this topic is well discussed in this thread:
http://www.hometheatershack.com/for...ice-needed-build-new-3-way-active-system.html


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## reed.hannebaum (Apr 21, 2006)

I feel biamping is a great way to go.For my front L/R speakers I chose to mate a subwoofer with each of my bookshelf speakers. I have tried several Xovers; Paradigm X-30, dbx 223, Beringer CX2310, and finally the NHT-X2. What disappointed me with most of these units was the circuit noise. Generally the more features you have in a unit (phase adjustment, slope adjustment, etc) then the designer is forced to introduce more opamps into the signal path, which creates noise, especially with the high frequency drivers. Also, discrete crossover frequency adjustment as apposed to continuously variable adjustment allows for simpler circuit design and less noise. I found the NHT-X2 to be a happy medium of cost, features, and very low to non-existent noise. Unfortunately this unit is no longer being made.
I also chose to go with a relatively high quality amp to drive the bookshelf speakers, and high power Class H subwoofer amp. A Class H amp is a cheap way of generating a lot of power at the expense of some harmonic distortion, but in a subwoofer you will never will hear it.


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## maschoemaker (Feb 6, 2010)

coony63 said:


> If you are interested in active crossovesr check out minidsp prossesers very slick units.


Or combine that with the MiniAMP, which seems ideal to use with the MiniDSP (allthough with 10 watts on 4 channels a bit weak)
If you do that, it's just a matter of putting up the right settings and all left is an electric plug, a cable to your sound source and a USB entry for chaninging the settings.

Or if you want to build a two way, get a Hypex AS2.100.
You can also make that a three way by combining that one with for instance a DS1.2 or 2.0 (subwoofer) amplifier and set the cross over frequency on the Hypex A2.100, creating a very nice high quality active three way


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## Mark Techer (Jan 17, 2008)

Zeitgeist said:


> I've seen some interesting plans for 2-3 way speakers that use active crossovers.. By active crossovers, I mean Behringer DCX2496 or some of the cheaper models.
> 
> However, with active crossovers and separate line level outputs - with a pair of 3 way speakers, you're looking at having 6 sources to amplify. What do most DIY builders do - when they need to amplify 4-6 channels for a pair of speakers?
> 
> ...


Last year I upgrades from passive to active. My project was to convert my LCRs from a 2 way passive system to a 2 way Active system. Because I have 3 identical LCRs, I would need 6CH of amplification. The challenge I faced was finding a suitable crossover to match my driver layout. These speakers have to fit into cutouts that are part of my baffle wall behind my AT screen, so it wasn't going to a case or a complete redesign unless I changed the baffle wall as well. I needed to find an active crossover close to the frequency I was using in the passive system in order to maintain the same driver spacing that controls the vertical dispersion of the speaker. The passive system uses 1550Hz which was proving to be a challenge as all the products I saw used higher crossovers.

Basically, as I searched the net for active crossover, I found a few products that would do the job, however hideously expensive by the time one added amplification. I even turned to JANDS who make active modules for JBL powered speakers and no luck on anything "affordable" as the cheapest units they had were over $1000 each.

I contacted the speaker company I buy my drivers from and asked what solutions they could offer. As it turns out, they were testing a small 2CH module with a 2K 4th order LR crossover and they seemed impressed with what they had. These modules have 70W LP and 30W HP and a 2K crossover. They praised the product, so I took a leap of faith and bought 3 units.

To convert my speakers from 1550Hz to 2000Hz meant I had to reduce the centre to centre spacing of the tweeters. I elected to have a new set of baffles made out of ABS plastic as opposed to the making new baffles from 25mm MDF. I also made myself some new trapezoid enclosures. Doing this added a few liters to compensate for what the 2CH amp module would take up as well as giving me the proven benefits of such a shaped enclosure - IE the two side walls are no longer parallel. 

The key being that in order to reduce the spacing, I had to over lap the drivers, so counter sinking the centre driver. I built my first speakers with controlled vertical directivity in 1998 and this is actually set 5 for me. Because those designs worked so well, I've continued to do the same thing for the different designs including these current speakers. 

Because my drivers are wired in parallel and the VIFA XTs I use a 4ohm, I had to make impedance matching for the HP section. The two woofers were 8ohm, so no problems there. Even though I use an 80Hz crossover to the LCRs, I still used a simple impedance network on the LP section. 

The modules are basic. They have a single RCA as the input and they have an IEC (jug cord) power socket. There is HP/LP trims and a power switch. The end result is they work well. They play loud and deliver greater dynamics than the previous passive speakers could offer.

Image 1: A simple diagram showing amplification after the crossover.
Image 2: The back of the Amp module.
Image 3: I used a double binding post terminal plate to connect the four wired from the AMP modules. Notice the bridging straps are removed. I then mounted the other components needed to back of the plate and this then was attached to the inside of the enclosure.
Image 4: New and Old side by side. 
Image 5: The back of the L and C speakers once the LCRs were installed back in the baffle wall.


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## Zeitgeist (Apr 4, 2009)

Very interesting Mark. I recall seeing that you had to change the spacing of your tweeters but didn't fully understand that it was due to a change in your crossover frequency.

I am going to post a build thread....but I'm working on a 3 way build.. I have a few Crown Microtech amps and for the short term going to use a JBL M553 (a 3 way stereo crossover). I plan on upgrading to a DCX2496 or DBX Driver PA+ and maybe QSC DCA amps to replace the Crowns.

Your setup looks great - especially with the modules. I'd love to buy some Digmoda modules....but they're not cheap and unfortunately Speakerpower is OEM only.

You said Vifa treaters...what did you use for woofers?


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## Mark Techer (Jan 17, 2008)

The drivers are all VIFA (XT super tweeters and P17 woofers) and infact the tweeters actually have "MADE IN DENMARK" on the magnetic shielding cups (yes I used shielded drivers as well). 

Late 2009/early 2010, I built two sets of the older passive design and the same model speakers have now "DESIGNED IN DENMARK". I am therefore left to assume that means made in China. Even so, China can produce some very high quality products and these drivers looked exactly the same and sounded beautiful once the systems were completed. 

As I understand it, VIFA and Peerless combined to produce PEERLESS AUDIO ENGINEERING (AKA PAE) and all the line are made in China, yet they perform well.

Yes the 2CH amp modules are neat and take out the excess cable mess that I had when I ran a car electronic crossover for bass management a few years ago. This is very PLUG N PLAY now. 

I've always been a fan of vertical directivity and thinking back, I've had some form of that for every speaker I've owned (hmm interesting). So it was just a case of working out what I needed to do to make it happen. 

So a three way? Single W M T or something like W MTM W? And yes, having heard the same drivers in a passive system, then active, the active is the way to go. Clean, powerful. I think I might have to go out and listen to them now


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## bambino (Feb 21, 2010)

With all the talk of the extra amp channels needed it got me thinking of how many i'll need, after the math i should have more then enough: 2 UPA-5's 1 XPA-5's and 2 XPA-1's that should be plenty enough to do 3 amp channels per speaker (L-C-R). One thing after reading a couple posts here is that i relized my tweeter is 4ohms as well as my mids, will that present a problem i'll need to over come or will i be good to go? my active crossover is a DCX2496.


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## Zeitgeist (Apr 4, 2009)

bambino said:


> With all the talk of the extra amp channels needed it got me thinking of how many i'll need, after the math i should have more then enough: 2 UPA-5's 1 XPA-5's and 2 XPA-1's that should be plenty enough to do 3 amp channels per speaker (L-C-R). One thing after reading a couple posts here is that i relized my tweeter is 4ohms as well as my mids, will that present a problem i'll need to over come or will i be good to go? my active crossover is a DCX2496.


Do you really have that much Emotiva gear? If so - I'm jealous! I have a UPA-7 which I love.

I think that almost any Emotiva gear can handle 4 ohms without a problem.

I think the one thing that you might run into - is whether you can cut the 4 ohm drivers enough to drive them at a similar level as the 8 ohm ones --- or boost the 8 ohms enough to get them to match. I think unfortunately, you can't adjust the gain on each channel of the Emotivas.

You thinking 2 or 3 ways? You'll need at least a couple more DCX2496s, I think.


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## Zeitgeist (Apr 4, 2009)

Mark Techer said:


> As I understand it, VIFA and Peerless combined to produce PEERLESS AUDIO ENGINEERING (AKA PAE) and all the line are made in China, yet they perform well.
> 
> So a three way? Single W M T or something like W MTM W? And yes, having heard the same drivers in a passive system, then active, the active is the way to go. Clean, powerful. I think I might have to go out and listen to them now


That's interesting aboue PAE. I recall reading about some recent(ish) changes that have occurred - regarding where they are actually made.

Yup........ a WCW
AE TD12S - Coax (B&C 8CXT) - AE TD12S

Crossover and EQ will be a bear, but should sound great!


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## Zeitgeist (Apr 4, 2009)

Mark Techer said:


> As I understand it, VIFA and Peerless combined to produce PEERLESS AUDIO ENGINEERING (AKA PAE) and all the line are made in China, yet they perform well.
> 
> So a three way? Single W M T or something like W MTM W? And yes, having heard the same drivers in a passive system, then active, the active is the way to go. Clean, powerful. I think I might have to go out and listen to them now


That's interesting about PAE. I recall reading about some recent(ish) changes that have occurred - regarding where they are actually made.

Yup........ a WCW
AE TD12S - Coax (B&C 8CXT) - AE TD12S

Crossover and EQ will be a bear, but should sound great!


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## bambino (Feb 21, 2010)

Zeitgeist said:


> Do you really have that much Emotiva gear? If so - I'm jealous! I have a UPA-7 which I love.
> 
> I think that almost any Emotiva gear can handle 4 ohms without a problem.
> 
> ...


Emotiva certainly makes some good amps and with there sales they have had lately it makes them hard to pass up (I think it's OCD,LOL). I'm not so worried about the amps being able to deliver as i am the level matching, i'm doing 3-ways with the center possibly being passive but haven't set that one in stone yet. I too wish there was some sort of gain control on the amps, who knows maybe the DCX will have some sort of feature like that i haven't had a chance to play with it yet and it will probly be a few months before i am able to actually sit down and mess with it as i like you have 200 projects going on top of hanging with the twins.:sn:


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## Mark Techer (Jan 17, 2008)

bambino said:


> With all the talk of the extra amp channels needed it got me thinking of how many i'll need, after the math i should have more then enough: 2 UPA-5's 1 XPA-5's and 2 XPA-1's that should be plenty enough to do 3 amp channels per speaker (L-C-R). One thing after reading a couple posts here is that i relized my tweeter is 4ohms as well as my mids, will that present a problem i'll need to over come or will i be good to go? my active crossover is a DCX2496.


For a 3 way active system, you will need 9 channels of amplification or three per speaker. 
I run 2 way LCRs, so I use 6. Some day, I'd like to extend that level of performance to the surrounds as well. I can only imagine what a active 3 way LCR array sounds (or is that pounds?) like  My 2 way LCR array lets you know it is running I can tell you. 



Zeitgeist said:


> That's interesting aboue PAE. I recall reading about some recent(ish) changes that have occurred - regarding where they are actually made.


Looking at the WES catalogue, it does appear that PAE is made in China. I am assuming the other VIFA and Peerless drivers are made there as well now. I choose VIFA because they were (at the time I started buying them anyway) made in Denmark. I'm sure the XLS woofers I use in my SUBs also have a place of manufacture as Denmark as well. I didn't see that on the last two sets I made. 



> Yup........ a WCW
> AE TD12S - Coax (B&C 8CXT) - AE TD12S
> 
> Crossover and EQ will be a bear, but should sound great!


Bear, is that the brand?

So is the mid/HF coax driver able to be powered separately or does the HF driver leach power off the Mid's amp and use passive components for for the Tweeter's LP and Mids HP? 

In my system, I have a 70 watt amp and a 30 watt amp. The 30 watt Amp drives the three tweeters with signal from 2K and up. I had to add resistance in series to the tweeters to bring the load back up to 4 ohm from 1.3ohm. These amp modules are actually designed around an 8ohm load (as are most AVRs), however I've been running 4 ohm loads now for 11 years and not fried anything yet.


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## bambino (Feb 21, 2010)

So with my mids and tweeters being 4ohms and the bass units being 8 do you think i'll have to add anything to attentuate the volume of the drivers or to get all the impedances to match?If so what would i use?:dontknow:




Thanks Jim for letting me Hijack your thread by the way. LOL.


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## Zeitgeist (Apr 4, 2009)

Mark Techer said:


> Bear, is that the brand?
> 
> So is the mid/HF coax driver able to be powered separately or does the HF driver leach power off the Mid's amp and use passive components for for the Tweeter's LP and Mids HP?
> 
> In my system, I have a 70 watt amp and a 30 watt amp. The 30 watt Amp drives the three tweeters with signal from 2K and up. I had to add resistance in series to the tweeters to bring the load back up to 4 ohm from 1.3ohm. These amp modules are actually designed around an 8ohm load (as are most AVRs), however I've been running 4 ohm loads now for 11 years and not fried anything yet.


Sorry! Meant bear as in tough!!

Crossover temporarily is JBL M553. Going to upgrade to DBX Driverack PA+ or DCX2496. The JBL is very limited. You pick crossover frequencies - and you can change gain for low/mid/high - but that's it.

I'm actually planning on going entirely active. Yes, it means more amps and more cabling... :hissyfit:

The coax mid/HF drivers are completely separate and require a crossover.. I forget what the efficiencies are - but it's a few db.. Enough that I've not given a whole lot of thought to trying passive. The HF driver actually radiates through the fabric dust cap of the midrange.


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## Mark Techer (Jan 17, 2008)

bambino said:


> So with my mids and tweeters being 4ohms and the bass units being 8 do you think i'll have to add anything to attentuate the volume of the drivers or to get all the impedances to match?If so what would i use?:dontknow:


I am not familiar with your design, but if it were my own, I'd be using two 8 ohm woofers in parallel which is then a 4 ohm load and up to 6dB more efficient than the single 8 ohm driver - basically, the amp does not have to work as hard to achieve the same SPL. Because you are going active, each band is managed independently, so you can run 4 and 8 ohm loads without incident. There should be trims on the HP to allow you pull down the level if it is too high. Drivers pending, you may need to install a passive L pad network to attenuate the HFs. In the case of my 2CH amps, they rely on this and why the HP section is just 30W. It needs the tweeter to be louder then the woofer. In my case, I made up that extra gain by wiring three XTs (they are only about 91dB, most tweeters are 94dB) and the three have given me some 8dB gain. Because I have used series resisters to bring the 1.3ohm load up to 4 ohm, I got a loss which has worked out to be pretty much right. 



Zeitgeist said:


> Sorry! Meant bear as in tough!!
> 
> Crossover temporarily is JBL M553. Going to upgrade to DBX Driverack PA+ or DCX2496. The JBL is very limited. You pick crossover frequencies - and you can change gain for low/mid/high - but that's it.
> 
> ...


If you can wing going fully active, don't bother with passive - phase changing, power robbing etc etc etc. The only reason most speakers are passive is cost. It is not even case of simplified wiring as mine have a single RCA in only, so provided the AVR has full pre-outs (all THX certified AVS do), it is all good.


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## Zeitgeist (Apr 4, 2009)

Mark Techer said:


> If you can wing going fully active, don't bother with passive - phase changing, power robbing etc etc etc. The only reason most speakers are passive is cost. It is not even case of simplified wiring as mine have a single RCA in only, so provided the AVR has full pre-outs (all THX certified AVS do), it is all good.


I have an Onkyo PR-SC886 w/RCA and XLR pre-outs... so I feel like I'm in pretty good shape to "play".

It was fun bundling 450 feet of speaker wire into 3 bundles of 3 runs each (Low/Mid/high cables in each bundle, and 3 bundles because of L, C, R). I did 50 feet runs so I have plenty of distance - even though it's way overkill. I wanted excess so I can figure out where I'm putting everything! So.. you talk of simplicity in wiring with your modules.. Yep.... That's for sure.


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## Mark Techer (Jan 17, 2008)

My original plan was to mount the 2CH amp modules in the EQ Rack and run extra cables to the speakers. I figured this might be OK, however as I went along, it was more of a pain than anything and I figured that since the SUB runs an RCA to its built in plate amp, why not do the same for the LCRs? And so that is what I did. All I had to change in my room was the RCA terminal plate (from single to multi) at each end of the room and run the 3RCA leads. I already had filtered power at that end of the room for the SUB, so that was a non issue as well. 

The bonus is that should I upgrade my AVR (and I will for 3D at some point soon) to have Z or height channels, the speaker cables are already in place. And I have over 200mm (8") of space above the screen, so a perfect place to mount them too.


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## Theresa (Aug 23, 2010)

I use active crossovers (miniDSPs) for all front channels. I have ten channels of amplification for my 5.1 surround setup. My amps are Emotiva and deliver anywhere from 140 watts RMS to 300. Getting it wired up was very complicated for me, I burnt out a tweeter while doing it. But even with the challenge of getting every driver hooked up with the same polarity and correct channel the sound benefits are tremendous. With the same brand of amplifier getting the levels correct is easier.


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## Zeitgeist (Apr 4, 2009)

Theresa said:


> I use active crossovers (miniDSPs) for all front channels. I have ten channels of amplification for my 5.1 surround setup. My amps are Emotiva and deliver anywhere from 140 watts RMS to 300. Getting it wired up was very complicated for me, I burnt out a tweeter while doing it. But even with the challenge of getting every driver hooked up with the same polarity and correct channel the sound benefits are tremendous. With the same brand of amplifier getting the levels correct is easier.


Since Emotivas don't have a gain knob for individual channels.. I assume the miniDSPs allow you to change the level of the signal enough - to level match the individual drivers?


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## bambino (Feb 21, 2010)

What is the model # for the miniDSP's that you are using? Thanks.


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## Theresa (Aug 23, 2010)

Zeitgeist said:


> Since Emotivas don't have a gain knob for individual channels.. I assume the miniDSPs allow you to change the level of the signal enough - to level match the individual drivers?


Yes of course. The miniDSPs have both input and output level controls. The output at max matches the Emos perfectly.
The one problem I''m having right now is that the output voltage is only .9 volts, just right for the Emos but too low to use a pro amp on the subs.


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## Theresa (Aug 23, 2010)

bambino said:


> What is the model # for the miniDSP's that you are using? Thanks.


I use a miniDSP In A Box type a (http://www.minidsp.com/minibox/minidsp-2x4, unbalanced). There are balanced versions too.


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## Zeitgeist (Apr 4, 2009)

Cool. Thanks for the feedback.

My concern wasn't just changing the gain.. but changing it ENOUGH to match the drivers... Since some drivers can be quite different in terms of efficiency.

Thanks!


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## reed.hannebaum (Apr 21, 2006)

Mark Techer said:


> I am not familiar with your design, but if it were my own, I'd be using two 8 ohm woofers in parallel which is then a 4 ohm load and up to 6dB more efficient than the single 8 ohm driver - basically, the amp does not have to work as hard to achieve the same SPL. Because you are going active, each band is managed independently, so you can run 4 and 8 ohm loads without incident. There should be trims on the HP to allow you pull down the level if it is too high. Drivers pending, you may need to install a passive L pad network to attenuate the HFs. In the case of my 2CH amps, they rely on this and why the HP section is just 30W. It needs the tweeter to be louder then the woofer. In my case, I made up that extra gain by wiring three XTs (they are only about 91dB, most tweeters are 94dB) and the three have given me some 8dB gain. Because I have used series resisters to bring the 1.3ohm load up to 4 ohm, I got a loss which has worked out to be pretty much right.


Therer has always been an argument about the importance of damping ratio. With your use of L-pads and series resistors you must feel there hasn't been any negative impact on sound quality? At any rate, this may not be an important factor with HF drivers.


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