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Looking for FIR capable DSP

NeoHippy

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Joined
May 9, 2024
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Hey,

I've been looking for DSPs for quite some time and never found the right one. Maybe some of you guys have suggestions?

What do i need:

Aes or spdif Inputs
Analog Inputs
At least capable of roughly 20k custom FIR taps in total at 48khz (4 x 4k taps + 2 x 2k taps)
6 analog Outputs possible
Additional standard dsp things like IIR eq, comp and limiter.
If it had a USB input as well that would be great, but is not necessary.


So I've looked into and worked with xilica solaros, they have some phase fuck up at 48khz in the audible range when using FIR. Also looked into raspi and camilla, but there you have sample rate Problem again and need to connect to USB for camilla_setrate and similar. Which is not practical. As the System should also run without a PC or USB connection.


I've seen the minisharc dsp boards. If I Use 2 of them they would have the necessary FIR power, but then again there are no minisharc DACs anymore. and also I'm wondering if using 2 modules is so good regarding Digital sync Problems (different jitter if its 2 boards etc).



So does anyone know a dsp which fulfills all criteria? Im also ok with using boards like mini sharc and doing some DIY stuff. But sound high quality is necessary. Also would be nice (maybe necessary) if i have a finished dsp GUI and dont need to Programm or develope everything myself.


Thanks in advance

Alex
 
I'm wondering if using 2 modules is so good regarding Digital sync Problems (different jitter if its 2 boards etc).
If the input is only analog, this should not be an issue. If you use digital inputs, it should not be a big issue either since the DSP ASRCs will convert to their local clock domain anyway. And usually there is an option to link/sync multiple boards as well.
Also looked into raspi and camilla, but there you have sample rate Problem again and need to connect to USB for camilla_setrate and similar. Which is not practical. As the System should also run without a PC or USB connection.
You should not need to change the sample rate, your DSP hardware will also not do that. Just run it at a fixed rate and let CamillaDSP resample to that rate.

Frankly, there aren’t any turnkey affordable solutions for this. You’ll always have to Frankenstein something to get it working.
 
If the input is only analog, this should not be an issue. If you use digital inputs, it should not be a big issue either since the DSP ASRCs will convert to their local clock domain anyway. And usually there is an option to link/sync multiple boards as well.

You should not need to change the sample rate, your DSP hardware will also not do that. Just run it at a fixed rate and let CamillaDSP resample to that rate.

Frankly, there aren’t any turnkey affordable solutions for this. You’ll always have to Frankenstein something to get it working.
Thanks for answering..


Which boards could you recommend?


Yes...but camilla can only resample if it gets the sample freq info via usb. (I've been asking about this in another thread and that's the way i understood it). So only Going into the audio interface which is hooked up to raspi+camilla with spdif, will only work if the spdif signal has the same sampling frequency as the camilla dsp is set to. To set camilla to new sampling frequency or have it resample you need gaudio_ctl or camilladsp-setrate, which both work as usb gadgets. Other dsps convert or adjust Sample rate automatically without beeing hooked up to USB..
 
Yes...but camilla can only resample if it gets the sample freq info via usb. (I've been asking about this in another thread and that's the way i understood it). So only Going into the audio interface which is hooked up to raspi+camilla with spdif, will only work if the spdif signal has the same sampling frequency as the camilla dsp is set to
I don’t think so. It has a resample module, right, you can just stick it to the input to convert the clock domain. At least, that would make sense..

Which boards could you recommend?
You tell me ;) I’ve been lurking at boards for a while, but I haven’t found any that I would be happy with. Definitely not is you need 20k taps.
So I've looked into and worked with xilica solaros, they have some phase fuck up at 48khz in the audible range when using FIR
Do you have a reference for this?
 
I don’t think so. It has a resample module, right, you can just stick it to the input to convert the clock domain. At least, that would make sense..

Could you tell me more about this? Are you sure this works in a FIR setup too? I'm no expert with camilla, so i can Just tell you what other people here told me. Maybe i understood it wrong. But what would be the use of setrate and similar if camilla could just resample by itself anyways?

You tell me ;) I’ve been lurking at boards for a while, but I haven’t found any that I would be happy with. Definitely not is you need 20k taps.
Aiaiaiaiai.....2 boards of minisharc maybe? Whats your opinion on them?


Do you have a reference for this?
I haven't saved the measurement where i directly measured xilicas output. So i can only show you the measurement with the xilica+ the HF transducer. But without FIR settings the phase response doesn't do that and is more or less flat. As well as the frequency Response. With FIR its all bent and weird close to the max frequency. This was at 48khz and as you see xilica starts fucking up way before half of that. FIR filters were simple xover at 3khz. Nothing else above or in the range where all is bent and weird
 

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I don’t think so. It has a resample module, right, you can just stick it to the input to convert the clock domain. At least, that would make sense..
CDSP can resample, but it must open the capture soundcard at some samplerate. Very few SPDIF input alsa drivers report the incoming samplerate as detected by the SPDIF receiver via dedicated alsa controls.
 
DEQX Premate, but it is very expensive.

Other than this, PC + soundcard is your best option. This is very painful to use with SPDIF/AES inputs though, so I feel your pain.
 
CDSP can resample, but it must open the capture soundcard at some samplerate. Very few SPDIF input alsa drivers report the incoming samplerate as detected by the SPDIF receiver via dedicated alsa controls.
Ah, so that’s the problem :rolleyes:. Sound like something that could be fixed in software in the future.

Another solution would be to add a hardware ASRC, so that the SPDIF input is always fed with the same sample rate. You’ll just need to add another leg to your Frankenstein monster ;)
 
DEQX Premate, but it is very expensive.

Other than this, PC + soundcard is your best option. This is very painful to use with SPDIF/AES inputs though, so I feel your pain.
Thanks! Yeah it is very expensive and also only 4 analog outs..i would need 6. (Pair of 3 way speakers, tri amped)

Yeah it is a pain it seems. But as the final product will also be sold, it needs to be versatile and have digital as well as analog Inputs..
 
Not sure why usb out is a problem for you. If you are capable, you can buy a adsp21569 evaluation board and figure things out.
 
Considered a Hypex Plateamp so far?
 
Hey,

I've been looking for DSPs for quite some time and never found the right one. Maybe some of you guys have suggestions?

What do i need:

Aes or spdif Inputs
Analog Inputs
At least capable of roughly 20k custom FIR taps in total at 48khz (4 x 4k taps + 2 x 2k taps)
6 analog Outputs possible
Additional standard dsp things like IIR eq, comp and limiter.
If it had a USB input as well that would be great, but is not necessary.


So I've looked into and worked with xilica solaros, they have some phase fuck up at 48khz in the audible range when using FIR. Also looked into raspi and camilla, but there you have sample rate Problem again and need to connect to USB for camilla_setrate and similar. Which is not practical. As the System should also run without a PC or USB connection.


I've seen the minisharc dsp boards. If I Use 2 of them they would have the necessary FIR power, but then again there are no minisharc DACs anymore. and also I'm wondering if using 2 modules is so good regarding Digital sync Problems (different jitter if its 2 boards etc).



So does anyone know a dsp which fulfills all criteria? Im also ok with using boards like mini sharc and doing some DIY stuff. But sound high quality is necessary. Also would be nice (maybe necessary) if i have a finished dsp GUI and dont need to Programm or develope everything myself.


Thanks in advance

Alex
As others have said, there’s no commercially available board that will meet your needs. Perhaps the best option is an audio interface plus a small fanless stand alone computer.

E.g. MOTU Ultralite 5 + i3/5/7 fanless PC.

Also see: http://archimago.blogspot.com/2024/02/hunsn-cwwk-rj36-fanless-minipc-intel-i3.html
 
Considered a Hypex Plateamp so far?
Hey,

Yes I have. But they don't offer what I need. Neither the FIR capability and also the amping itself isn't quite there where i want it. It's not bad or anything and we are going with HYPEX amps. But with the NCX modules, which are better than the one in the plate amps..
 
As others have said, there’s no commercially available board that will meet your needs. Perhaps the best option is an audio interface plus a small fanless stand alone computer.

E.g. MOTU Ultralite 5 + i3/5/7 fanless PC.

Also see: http://archimago.blogspot.com/2024/02/hunsn-cwwk-rj36-fanless-minipc-intel-i3.html
Yeah... honestly its a little annoying for me to have another.PC in the chain. But it seems there is no other options. But if i go with it, it wouldn't be a windows system. It's gonna update over time or make some other problems eventually. Better stick with linux
 
Yeah... honestly its a little annoying for me to have another.PC in the chain. But it seems there is no other options. But if i go with it, it wouldn't be a windows system. It's gonna update over time or make some other problems eventually. Better stick with linux
A SBC is sufficient for the job.
 
Hi. I recommended the BSS London-806DA. It meet all your needs plus more. You can choose between two sample rates: 48K or 96K. I recommend 96K, it will give you less latency and your FIR will take less time. Pictures below of your case setup. Each FIR filter is using 4096 taps. The max is 6700 taps per FIR filter.

Block Diagram
1717258204654.png


Crossover
1717258339616.png


IIR eq
1717258440117.png


Compressor
1717258488463.png


Limiter
1717258513288.png


Analog Input
1717258547906.png


Digital Imput
1717258576150.png


Analog Output
1717258605485.png


Overal DSP used %
1717258649518.png
 
Hi. I recommended the BSS London-806DA. It meet all your needs plus more. You can choose between two sample rates: 48K or 96K. I recommend 96K, it will give you less latency and your FIR will take less time. Pictures below of your case setup. Each FIR filter is using 4096 taps. The max is 6700 taps per FIR filter.

Block Diagram
View attachment 372517

Crossover
View attachment 372518

IIR eq
View attachment 372519

Compressor
View attachment 372520

Limiter
View attachment 372521

Analog Input
View attachment 372522

Digital Imput
View attachment 372526

Analog Output
View attachment 372527

Overal DSP used %
View attachment 372528
Hey man,

Thanks a lot for your input! Sure seems like a great DSP. I am going to look into that!

Thanks again for all your effort!
 
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