Digital crossover and room equalisation

[oon_the_kid]

Hi,

I am looking to buil/purchase a dsp for room equalisation and digital crossover. Ideally it would also have digital amp connected to it. I am looking at available options.

Those that I am/have considered>

1) MiniDSP from minidsp.com the combo including digital amp for US$200. ( Most likely candidate)

2) Behringer Ultracurve and behringer digital crossover. ( a bit too expensive for my budget, about US$650)

3) PC-based software (for equalisation and crossover) followed by external USB DAC. (I like the idea, but clueless how to implemement this, is there a software one can purchase/download that can do this?)

And any other options that you may know of, please do let me know, Old Home thearte system etc...

Oon

[zlac]

Few days ago, I stumbled on thing you might be interested in:
DSP Crossover for PC. Frequency Allocator.

It's PC based software called "Loudspeaker Frequency Allocator".
I don't need it because I use a full range speakers so I don't know much about it.
I accidentally stumbled upon it when I was in a thought process on how I would do it for a friend of mine. I think that this software needs multi channel soundcard with ASIO support, you just create equalization and crossover curves in it and then you map it to your soundcard outputs and it works.
You could probably also use your digital exit with it.
I think it costs about 150$.

If you buy MiniDSP, you can buy their "STEREO CROSSOVER PLUG-IN" or something similar for 10$

I was thinking of make something similar with Foobar convolver. I would use "Convert stereo to 4 channels" DSP and then I would put 4 channel impulse file in convolver DSP. It would have lowpass filter on front speaker channels and highpass filter on surround speaker channels... then I would just plug big drivers to front plug and tweeters to surround plug.
Unfortunately, it can't work with foobar convolver because convolver DSP says "unsupported channel count" or something like that when you feed it 4 channel impulse file, it only works with stereo... maybe if we can contact the guy that made convolver and sweet-talk him to do 4 or 6 channel convolver, it would be sick and could possibly replace multi 1000 dollar systems if you know how to properly make your impulse files for DRC and crossovers.

If you already have or if you can make room equalization impulse file, you can convolve it with frequency sweep, then you save it twice and use highpass on one and lowpass on the other. Then you deconvolve each one of them to get two impulse files (you could make 3 if you need lowpass, bandpass and highpass).

The cheapest but most time consuming way of using those would be duplicating all your music, using one impulse file on one version and other impulse file on other version, then you can connect those to multi channel audio so you simply play them in foobar and you connect your speakers just like you would connect them if you used frequency allocator. More expensive way would be feeding those impulse files to a dedicated DSP hardware (or software) that can use convolution.

You can make your own impulse files by making frequency sweep, equalizing and modifying it however you want and then you deconvolve it with something like Voxengo Deconvolver (you must also have non modified sweep to do it).
I'm using 96kHz, 32bit float wav file with 100s sweep from 10Hz to 21000Hz for that purpose, I made quite complex equalizer with that technique, it even kills some of the resonance of my room and speakers and I'm tweaking it every few days, it sounds fantastic right now and that impulse file is only 350ms long.

[DualTriode]

Originally Posted by oon_the_kid

Hi,

I am looking to buil/purchase a dsp for room equalisation and digital crossover. Ideally it would also have digital amp connected to it. I am looking at available options.

Those that I am/have considered>

1) MiniDSP from minidsp.com the combo including digital amp for US$200. ( Most likely candidate)

2) Behringer Ultracurve and behringer digital crossover. ( a bit too expensive for my budget, about US$650)

3) PC-based software (for equalisation and crossover) followed by external USB DAC. (I like the idea, but clueless how to implemement this, is there a software one can purchase/download that can do this?)

And any other options that you may know of, please do let me know, Old Home thearte system etc...

Oon

Hello Oon,
Your option #2 need not cost that much. It looks like you are thinking two pieces of equipment; equalizer and crossover. The DCX 2496 is a crossover plus it has built in equalizers too. Perhaps you can download the manual and check out the functions to confirm that they meet your needs or not.
For your option #3 there is Ultimate Equalizer that uses your PC and sound card for digital XO, equalization and DAC. There is an online manual for this as well.
DT
All just for fun!

[adhiyasa38]

Hi oon,
I pointed to :
1. Behringer, - Not good in analog input output, excellent in digital area.
for equalizer DEQ, i prefer to use digital in and out.
Excellent room /speaker equalizer, you can measure freq response via microphone, adjust as your tastes.

Output behringer DCX you can choose 2 way or 3 way, graph x over, drive 2 way or 3 way, to amplifier

2.Another option, if you like to adjust via software, choose evaluation board from Analog devices, search google Evaluation board ADAU 1761.

[oon_the_kid]

Hi,

Thanks, I was considering this option, then I realised that a multichannel DAC would costs just as much as a minidsp. so there is not much benefits there.

Oon

Originally Posted by zlac

Few days ago, I stumbled on thing you might be interested in:
DSP Crossover for PC. Frequency Allocator.

It's PC based software called "Loudspeaker Frequency Allocator".
I don't need it because I use a full range speakers so I don't know much about it.
I accidentally stumbled upon it when I was in a thought process on how I would do it for a friend of mine. I think that this software needs multi channel soundcard with ASIO support, you just create equalization and crossover curves in it and then you map it to your soundcard outputs and it works.
You could probably also use your digital exit with it.
I think it costs about 150$.

If you buy MiniDSP, you can buy their "STEREO CROSSOVER PLUG-IN" or something similar for 10$

I was thinking of make something similar with Foobar convolver. I would use "Convert stereo to 4 channels" DSP and then I would put 4 channel impulse file in convolver DSP. It would have lowpass filter on front speaker channels and highpass filter on surround speaker channels... then I would just plug big drivers to front plug and tweeters to surround plug.
Unfortunately, it can't work with foobar convolver because convolver DSP says "unsupported channel count" or something like that when you feed it 4 channel impulse file, it only works with stereo... maybe if we can contact the guy that made convolver and sweet-talk him to do 4 or 6 channel convolver, it would be sick and could possibly replace multi 1000 dollar systems if you know how to properly make your impulse files for DRC and crossovers.

If you already have or if you can make room equalization impulse file, you can convolve it with frequency sweep, then you save it twice and use highpass on one and lowpass on the other. Then you deconvolve each one of them to get two impulse files (you could make 3 if you need lowpass, bandpass and highpass).

The cheapest but most time consuming way of using those would be duplicating all your music, using one impulse file on one version and other impulse file on other version, then you can connect those to multi channel audio so you simply play them in foobar and you connect your speakers just like you would connect them if you used frequency allocator. More expensive way would be feeding those impulse files to a dedicated DSP hardware (or software) that can use convolution.

You can make your own impulse files by making frequency sweep, equalizing and modifying it however you want and then you deconvolve it with something like Voxengo Deconvolver (you must also have non modified sweep to do it).
I'm using 96kHz, 32bit float wav file with 100s sweep from 10Hz to 21000Hz for that purpose, I made quite complex equalizer with that technique, it even kills some of the resonance of my room and speakers and I'm tweaking it every few days, it sounds fantastic right now and that impulse file is only 350ms long.

[oon_the_kid]

Hi DT,

Thanks, Let me have a closer look at it. I was looking at it didn't realise it has a built in equaliser.

Oon

Originally Posted by DualTriode

Hello Oon,
Your option #2 need not cost that much. It looks like you are thinking two pieces of equipment; equalizer and crossover. The DCX 2496 is a crossover plus it has built in equalizers too. Perhaps you can download the manual and check out the functions to confirm that they meet your needs or not.
For your option #3 there is Ultimate Equalizer that uses your PC and sound card for digital XO, equalization and DAC. There is an online manual for this as well.
DT
All just for fun!

[oon_the_kid]

Hi Adhiyasa38,

Thanks for the tip, the minidsp uses ADAU 1701. As for the evaluation borad, sound like a cool idea, but unfortunately I know nuts about programming such stuff... So will pass this idea for now..

Oon

Originally Posted by adhiyasa38

Hi oon,
I pointed to :
1. Behringer, - Not good in analog input output, excellent in digital area.
for equalizer DEQ, i prefer to use digital in and out.
Excellent room /speaker equalizer, you can measure freq response via microphone, adjust as your tastes.

Output behringer DCX you can choose 2 way or 3 way, graph x over, drive 2 way or 3 way, to amplifier

2.Another option, if you like to adjust via software, choose evaluation board from Analog devices, search google Evaluation board ADAU 1761.