# Crossover for 4amp biamp



## sawyer (Feb 10, 2013)

I want to see what changes biamplification. I think an analog ActiveCrossover would be helpful.- any suggestion? I see lots of Rane AC 22 for $200.

Integra dtr7.8 A/V reciever pre-outs to Rane AC 22 to four Hafler se240 amps to pair of Paradigm studio 60 v3 

No modifications just remove the clips to allow the speakers to biamp.

At some point move forward with spl measurements and some analysis. I will have to ask that question in a different forum. I noticed the minidsp appears to be offer capabilities which may be of interest separately possibly before the the A/D. Maybe I want to try one then the other.


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## AudiocRaver (Jun 6, 2012)

I have no experience with that crossover, but Rane is a first-rate brand and it has everything I would be looking for, L-R, 24db/oct, delay management, even balanced i/o. I always get a little tweeter-cautious when thinking of bi-amping, but it sounds like you know to proceed with caution.

The miniDSP is another good option, nice because of its flexibility, if you decide not to bi-amp there is more you can do with it, while the Rane is off to eBay land.

I assume you are armed with calibrated mic and REW so you can share lots of measurements with us.


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## Kal Rubinson (Aug 3, 2006)

sawyer said:


> No modifications just remove the clips to allow the speakers to biamp.


Do you mean just removing the external jumpers or opening the boxes to wire directly to the drivers? If the former, the internal filters are still in operation.


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## sawyer (Feb 10, 2013)

For the Paradigm Studio 60 v3 I will simply remove the bar in the terminal cup that ties the two separate pairs of terminals together. 

I need to confirm assumptions for the setup with Paradigm: There are two separate signal paths one to a low-pass filter to the woofer and one to a high-pass filter to the tweeter/midrange. I want to confirm the extent to expected resistors in the crossover reduce power to tweeter. I want to know to what extent I am protected or alternately need to exercise care in overpowering the tweeters. I have the expectation that 200w max can be supplied to the high-pass terminals as Paradigm states for the speakers. My four Hafler amps are 120wpc stereo but 350w mono so that mode is not useable.

I have the expectation that it is not material to the speakers themselves that I place I put an active crossover in line before the amplifiers. The built in Paradigm passive speaker crossovers are still there filtering the frequencies and protecting the tweeter.

I do want to know what happens with the amplifier output when it is supplied only with the output of the active crossover as opposed to full range signal - seeing what happens with verticle bi-amping for this amp.

Perhaps for comparative purpose rather than listening perhaps the preout goes to the Rane AC 22 to minidsp1 to amp to minidsp2.

A few questions come to mind with variations in this non-listening setup assume the Rane AC 22 is "high-pass" for this conneciton
-without mindsp1 - just look at what minidsp2 says about the "high-pass" signal with and without the Rane AC 22 - this is really the stated objective
-with minidsp1 - what does minidsp2 say about what minidsp1 does to the signal in general and specifically as a replacement to the Rane AC 22.

I have an expectation but not an assumption if the the setup is controlled that If I don't see any thing different then I won't hear anything different.
It is an open question if I see anything different that I will actually hear the difference. If I hear a difference I wonder if I will like the difference.


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## AudiocRaver (Jun 6, 2012)

You have some interesting experiments in mind. Looks like a lot of it is focused directly on amplifier performance in a bi-amp situation, if I am reading correctly. It seems like that will require a very detailed analysis of distortion characteristics, as it seems (guessing here) that any differences would be small. They would be loaded measurements, I assume. Fun times ahead for you!


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## sawyer (Feb 10, 2013)

Yes, I expect room eq changes to be more readily measured and perceived than working at this location of verticle biamp in the source to listener chain.
I would like to avoid a very clerical detailed analysis in favor of something detailed but leveraging dsp.

To inform the questions I put above I would be interested in running the trials at the same time capturing the respective signals, performing an FFT on the data points and then subtracting the FFT result of each trial from each other and displaying the result. FFT is fast fourier transform which translates the frequency distribution of the power in a sound to a nice bar chart showing the amount of power at each frequency.


This would have the advantage that I would play music the I like and the variable load produced by my speakers as a function of frequency would also be included.

I noticed the Behringer Ultra-Curve Pro DEQ2496 Mastering Processor has an FFT but i don't think it is available to a pc their website has no manual. This gear is readily available on ebay. I think anyting that gives me essentially two columns of a spreadsheet would work as a difference can easilyt be calculated and plotted from that.


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## AudiocRaver (Jun 6, 2012)

Room EQ Wizard's RTA mode performs spectrum analysis like you are describing, an analysis plot can then be saved and exported in text/numeric form. Using a sound card input as a "scope input" into REW might do just what you need. Just a thought.


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## RTS100x5 (Sep 12, 2009)

This BEHRINGER unit will give you more customization than you can imagine at a very good price 

http://www.parts-express.com/pe/showdetl.cfm?partnumber=248-669


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## sawyer (Feb 10, 2013)

This BEHRINGER unit looks quite interesting. The reviews uniformly were giving it top rating as a loudspeaker managment processor providing all manner of functionality to produce a great result - only one reviewer wasn't a fan of the active output stage. Thanks for the reference.


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## sawyer (Feb 10, 2013)

I need help getting started with a baseline with this project, time-challenged, taken me a year to get to this point.

I just purchase an active crossover, see below, and have one last item to acquire to get started quickly for a baseline. 

Here is the equipment for the baseline measure in sequence from source to target. I need to quickly purchase a lost cost target/analysis to implement baseline test. Please provide specific confirmation and next step.

Baseline- 
Generate a controlled source signal from PCc - white/pink noise; detect/capture analyze in environment with microphone and save result to pc.


Process chain-
PC
hdmi cable out, 
integra-dtr-7.8 av receiver hdmi input
Rca preamp out, rca-to_xlr cable (2x)
Samson active crossover (see link to manual)
xlr_to_rca cable (4x), 
four hafler se240 amps (120wpc), 
12 awg speaker wire 20' 4pr
biamp bar removed, otherwise unmodified, Paradigm 60 V3 (see link to 1974 STEREOPHILE_Studio60_Review.pdf)
**umik-1 microphone
**cable to PC
** REW software on PC
--please confirm next step purchase umik-1 microphone and download REW software, secure white/pink white noise internet source
-- basic initial (simplest quickest possible) generation and data capture.


you will note in the prior thread it was identified "back to ebay" as a short term limited capability the purchase of a dedicated crossover. That is accurate, I want an outcome and having spent $500 and 1 year elapsed time to get to this point I want to get a quick baseline outcome to enable me to progress moving forward.

This is a combined horiz and vertical biamp. I think one side benefit will be to cross check my gear initially. As this biamp configuration only uses 1 channel of each amp and there are four amps, I think I can rotate through connections and amps performing the same test multiple times. With nothing else changed I should get essentially identical results on all configurations of cabling to inputs of amps and amps. Four stereo amps provides 8 pathways. Taking one signal path for example Left Speaker Hi Frequency - I could run eight tests of that one signal path by changing the signal path and amp. Actually, the Hafler SE240 also has a mono switch so that would mean 3 different configs per amp or 12 pathways that could be tested with the same test signal.

I am not touching the speakers, not removing their crossovers, simply removing the existing biamp strap. Nonetheless I may not attempt the "mono switch" choice with the HI (tweeter) as the amp output in mono bridged mode in which the amp provides a max of 350wpc.
With the safey of my speakers in mind I am not confident the crossover network provides sufficient protection. I would also like to do a pre-baseline checkout connecting the speaker wire to some other imdepdance device and capture device to allow me to see any transients that occur when turning on/off devices and changing volume level and also take the room sound characeristic out as a variable for pre-checkout. Another option could be to purchase some very common inexpensive (and expendable) speaker for checkout and more universal report out baseline results

This post ask for your prescriptive input. I appreciate your input /recommendation. I think it is more time efficient/effecitve to just identify your assumption and make your technical recommendation for what specific step to take please. Hopefully someone's input is going to help me move forward by just spending another $100 or so and investing another 4 hours to get the first result over an elapsed time of 1 week. This would mean moving forward with an online purchase in the next three days. I do have the Audessey mike as well as a Blue Yeti USB microphone - I hear they are not suitable and am looking for a quick sure thing mic implementation that has common usage. It took 30 minutes to type this up, hopefully I can get some traction with a response, thanks


Example initial capture setup instruction (partial)
http://www.minidsp.com/applications/acoustic-measurements/umik-1-hdmi-on-windows

SAMSON S 3-WAY STEREO/MONO CROSSOVER 2 CHANNEL
http://www.samsontech.com/site_media/legacy_docs/S3way own man_4lan.pdf

Paradigm Studio 60 analysis
http://www.paradigm.com/downloads/STEREOPHILE_Studio60_Review.pdf

Hafler SE240 Amp manual 120wpc stereo, 350wpc mono bridged mode
http://www.hafler.com/techsupport/pdf/SE240_amp_man.pdf

Integra DTR-7.8 A/V Receiver Manual
http://filedepot.onkyousa.com/Files/own_manuals/DTR-7.8_En_A.pdf


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## Wayne A. Pflughaupt (Apr 13, 2006)

I wish I had seen this thread when you first posted it; I maybe could have saved you a lot of time and expense.

There are at least a few benefits to active bi-amping. One naturally is the ability to customize the crossover frequencies and slops. Another is that drivers often sound much better with all those passive elements out of the signal chain. 

A third is greatly increased efficiency, as passive crossovers are power soaks. I remember a source I saw many years back that said that the SPL output you can get from a two-way speaker bi-amped with a pair of 50-watt amplifiers, would require a 250 watt amp if the speaker had a passive crossover. That should give you some idea just how much power is lost with passive crossovers.

Perhaps you can see where I’m going with this: By leaving the Paradigm’s passive crossovers in place, you are gaining absolutely no benefit from active bi-amping. (In fact, technically it’s not “active bi-amping” if there are passive crossovers in the signal chain.) Basically any crossover frequency you dial in with the Samson will be over-ridden by the passive crossover, so what’s the point? Sure, you _could_ get some flexibility in the crossover slope, but that’s probably not going to get you anything audibly beneficial without being able to tweak the crossover frequency as well. So basically, the Samson is going to benefit you nothing at all: If you really intend to keep the Paradigm’s stock crossovers in place, you would get the same effect by simply driving the amplifiers straight to the unstrapped speaker terminals – “passive bi-amping.”

I can understand that you’re worried about protecting the Paradigm’s drivers. Naturally the most fragile driver is the tweeter. However, that’s what the crossover is for, be it passive or electronic: to protect the drivers. Really, the only way to blow a tweeter or midrange driver is to dial in a substantially lower crossover frequency than the stock crossover. Trying to drive tweeters or mids with a lower-frequency signal than they can handle, that’s the way they get blown. You don’t really have to worry about overpowering the drivers, because actively bi-amped with the electronic crossover, the speakers will have such a tremendous increase in output for the wattage input, you’ll ultimately be only be using a fraction of the Hafler’s maximum power output.

Regards, 
Wayne


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## sawyer (Feb 10, 2013)

Please if anyone can detail/confirm the completion steps/gear for the source generation and capture, thanks


Statement has been made that there is less advantage with this setup of active crossover followed by passive crossover due to:
1) Passive crossover will continue to shape the input signal
2) Power loss in this configuration produces a 5:1 ratio disadvantage over active only without passive.
Suggestion was made that these two factors are dominant and by their presentation will mask other lower order effects in the measure such that other differences may not be distinguished.

Thanks for these two points, duly noted.


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## sawyer (Feb 10, 2013)

bump - anyone have clear step for microphone and rew or other s/w for baselining equipment?
As this is older gear purchased used which seems to work great, interested in pre-baselining/ verifying all identical components function similarly before moving forward with biamp measures. need to buy mic and get s/w

Attached photo of AV closet with two av receiver integra dtr-7.8 with four hafler se250 amps. 209.8lb total weight 2x50.9lb+4x27lb require separate shelf support. lazy Suzanne to position receiver for wiring.


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## sawyer (Feb 10, 2013)

bump- still researching the way to pre-baseline this setup -
I prefer absolute spl measure - for one reason - managing my inventory of gear (three integra dtr-7.8 receivers;4 hafler se-240 amps; 2 Paradigm Studio 60 v.3; 6 Paradigm 7 Mk3;2 Paradigm 5 Mk3) and concerned about sound isolation ie quiet rock, greenglue treatments and room treatments etc). The managing gear inventory means I need to know the gear is calibrated and 1khz tone input comparing amp out with multimeter a/c left and right channels raises more questions than answers.

With that said, my assumption is that i require a calibrated (frd file) mic from 
http://www.cross-spectrum.com/measurement/calibrated_dayton.html - choosing only from their offering of
miniDSP UMIK-1 USB
http://cross-spectrum.com/galaxy
http://www.cross-spectrum.com/umm6
http://www.cross-spectrum.com/umik1
and the non usb emm6
http://www.cross-spectrum.com/dayton
the non-usb emm6 would be coupled with a pc interface box
http://tascam.com/product/us-144mkii/

From this offering, they offer basic and premium (+$15) calibration for each of the three mics
Additionally, I see an spl microphone offered the model galaxy cm-140
http://cross-spectrum.com/galaxy

Unfortunately, only the galaxy cm-160 spl meter model 160 offers internal storage for an extra $100 though there is an AC Signal Out (note to followup on how to cable and capture that on pc)

I do see folks like to have an spl mike together with their microphone to assist on setup.
I also see that usb mic is generally sufficient over the previous standard requirement for a pc interface box supplying phantom power though some more advanced tests including time base correction benefit from the pc interface box.

Additionally the two usb mics appear to have inferior specs to the emm-6, though i will point out as someone else did here that this is an order of magnitude less than room effect.
Another criteria in the purchase would be the mic integration with minidsp, obviously one of the options is to choose the umik1. Further this setup would require two minidsp 2x4
http://www.minidsp.com/products/minidspkits/2-x-in-4-x-out
this unbalanced 2in4out at $80 an easy entry. Please correct me but the minidsp streamer box does not offer phantom power and is not an alternative to the tascam 122/144. 

It would be good to buy minimal gear though the new hdmi input raw/pcm product announcement for $300 that http://www.minidsp.com/images/documents/nanoAVR User Manual.pdf is interesting.

I received the S3 Stereo/Mono Active Crossover purchased on Ebay as well as six 6' and 10' xlr-rca cables from monoprice. I note on this forum a member identified mid 2013 issue with bad batch of xlr cables from monoprice so once this gear is connected that will be an item to report out the status of these cables.

So to recap next step is to 1) purchase a mic and spl meter for absolute spl and (likely) time corrected for REW. I think because I am going to use this gear in my residence only - the setup ie walls aren't moving anytime soon. It will be better to put in place moderately permanent baselines so the timecorrection and asbsolute spl are requirements.


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## sawyer (Feb 10, 2013)

correction to last post "Further this (crossover) setup would require *one* minidsp 2x4"


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## sawyer (Feb 10, 2013)

above Feb 2014 product link to manual on minidsp is the $300 nanoAVR, a 2-input HDMI audio and video switch combined with a high-resolution 8-channel audio processor


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## ajinfla (May 10, 2009)

Ok, I've read the thread and I'm at a complete loss here. What are you doing/hoping to do?


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## Wayne A. Pflughaupt (Apr 13, 2006)

He wants to bi-amp his speakers using both an electronic crossover and the speakers’ passive crossovers, and use REW to get baseline data for both the speakers and his electronics, but he can’t decide what hardware to get to facilitate REW. I think that’s it in a nutshell. :T

Regards, 
Wayne


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## ajinfla (May 10, 2009)

Wayne A. Pflughaupt said:


> He wants to bi-amp his speakers using both an electronic crossover and the speakers’ passive crossovers, and use REW to get baseline data for both the speakers and his electronics, but he can’t decide what hardware to get to facilitate REW. I think that’s it in a nutshell. :T
> 
> Regards,
> Wayne


Superimposing an electrical filter on an already electro-acoustically filtered full bandwidth system, unless related to subwoofers, is ill-conceived. That's a very bad idea.
Thanks for clarifying Wayne.


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## sawyer (Feb 10, 2013)

The next step identified is selection of additional gear to allow checkout of the setup. 
Some redundant measures and equipment allow for cross checking components
Longitudinal capture allows for long term setup and observation
Current bill of materials $500.
Providing Absolute SPL and time correction

The candidate purchase is on hold pending resolution of a data logging capability for the spl meter. The built in option adds $200 to bom.

prefer data logging capability for spl meter as well. 
cross-spectrum premium-plus calibrate frd emm-6 and galaxy cm-140
1) emm-6
2)galaxy cm-140
3)tascam us-144 
4)On Stage Stands MS7701 Tripod Boom Microphone Stand
5) 40' xlr cable (mic to tascam)
6)? DAQ data logger from dataq.com for 0-1v pp galaxy ouput
7)2x4 minidsp
above items: 
50+120+110+30+30+50+90=$480

"duly noted" on the critique of the strawman point objective posted here however it works for me as an organizing approach, views and comments always appreciated.


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