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Crossover implementation via MacBook Pro

andreasmaaan

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#1
I’m planning to build a pair of 3-way speakers for my living room using some drivers I have lying around and a set of ICEpower amp modules.

My remaining problem is the crossover. I have an old bunch of minidsp 2x4 + minidigi modules that I could use. However, the audio performance isn’t great (but is ok), and only IIR filters are available. It would be nice to experiment with FIR filters since I haven’t used these before.

I’m trying to do this on the cheap and have already exhausted the budget on amps and woofers, so buying more expensive crossover components is probably not an option.

I was thinking there might be an interesting solution involving the MacBook Pro that we play all our media off and a MOTU Ultralite that I also have sitting unused atm. Perhaps using something like Reaper and a suitable plugin?

Or how would one go about this?

Thx :)
 
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#2
Hi,
some time ago I build a pair of open baffle speakers and used the Sure/Wondom DSP as crossover and EQ. You can set it up to 24bit 192khz. There are many functions you can use. The processor with the expansion board can handle 2 ADC and 4 DAC (2 ADC and 3 DAC accessible with cinch expansion board) You can set manual EQ or use the Auto EQ calculator with its settings. You need 1 programmer, the free software, 1 processor board per channel and 1 expansion board per channel if needed. With 1 input you can use the 4 DACs for up to 4 way speakers then. The bitrate and khz are dependent on the used program items in the programm sketch. There are hundrets of function blocks to choose from. Optional is a measure microphone and REW software.
The complete setup would cost around 90 Dollar incl. programmer. Its a bit tricky but if needed I can make a tutorial from beginning to end.

A 2 way setup is my all day crossover and EQ, 12db/o at 450hz for my DIY open baffle. With my old DIY Vulcan Fostex full range setup it was the EQ and SUB pre Out.
 
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andreasmaaan

andreasmaaan

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Thread Starter #3
Thanks @quorzar, interesting idea. I’ve actually got one of those boards already for another project. I hadn’t realised it was possible to output digital audio from it to external DACs. This is without the RCA daughter board option I guess?
 
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Hmm ok. Then I didnt get all what you wrote, but in digital format its only possible to send out one stereo pair through the I2C bus with the PINs shown in the datasheet. And yes, you dont need the RCA board. But why dont use the onboard DACs? I think that they are not that bad.
 
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andreasmaaan

andreasmaaan

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Hmm ok. Then I didnt get all what you wrote, but in digital format its only possible to send out one stereo pair through the I2C bus with the PINs shown in the datasheet. And yes, you dont need the RCA board. But why dont use the onboard DACs? I think that they are not that bad.
Ok yes got it. I already have the minidsp+minidigi which has the same DSP chip IIRC, plus the ability to sync all 8 channels to the same master clock. So the Sure boards would be a step down in that respect, ie each channel would require a separate board with independent clocks. Also I know how the minidsp measures whereas I don’t know about the Sure. I’m sure it’s also quite ok though :)
 

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