ALL digital DSP (in & out)... What are the options?

[JonBocani]

Ok, so there is the nanoDigi... but what else ?

 

[CharlieLaub]

How many channels in and out?

What sample rates?

Hardware solutions only, or is software DSP also OK?

 

[JMF11]

Hi,

I'm very slowly exploring the potential of http://www.st.com/content/st_com/zh/products/evaluation-tools/product-evaluation-tools/mcu-eval-tools/stm32-mcu-eval-tools/stm32-mcu-nucleo/nucleo-f767zi.html.

That board has the potential for:
- SPDIF in, I2S in, Async USB in,
- sofware DSP (using outputs of Charlies ACD tools 🙂
- up to 4 stereo channels (I2S or SPDIF).

But no cool configuaration tool à la MiniDSP. Only C code (which as a tradeoff gives access to all the hardware features).

My objective is to have an operational USB=>Soft DSP=> 2 SPDIF stereo channels.

I propose this just in case you love those types of things and would be happy to investigate that option. This is for sure not the shortest path.

JMF

 

[JonBocani]

How many channels in and out?

What sample rates?

Hardware solutions only, or is software DSP also OK?

standalone hardware solutions only.

any sample rates

2ch in/8ch. out
(4-way speakers)

 

[Davey]

The miniDSP miniSHARC is DSP in and out. I2S, not S/PDIF.

Dave.

 

[stolbovoy]

Is there anything around that can handle 2 inputs 8 outputs on 192kHz and be slaved to DAC clock without ASRC?

 

[audionootje]

Would the najda board be an option?
WAF-Audio

 

[stolbovoy]

Najda looks really nice. Does it accept external clock? Is there digital only version?

 

[bobthedespot]

I have the stm32f769 disco board, and it rocks. You might consider it... spdif in and out, with a touchscreen and sd card slot for storage. Total cost is 80 bucks from mouser.

 

[stolbovoy]

I have the stm32f769 disco board, and it rocks. You might consider it... spdif in and out, with a touchscreen and sd card slot for storage. Total cost is 80 bucks from mouser.

Thanks! This looks interesting... Do I read the specs correctly and it supports 5 I2S interfaces: 2 SAI + 6/3 SPI/I2S?

 

[bobthedespot]

Yup. Best kept secret... used in the JRDG Daemon. TouchGFX offer super simple tools to build it into an integrated chassis.

 

[stolbovoy]

And it has free evaluation!
Any good resource on writing filters and audio related stuff with STM32?

 

[bobthedespot]

Yup 🙂

I do it for my day job using matlab etc, and I use ninja.

 

[TNT]

Get 4 of these: https://www.minidsp.com/products/opendrc-series/opendrc-di

and 2 of these: White Mini Portable SPDIF Toslink Digital Optical Audio 1 x 3 Splitter | eBay

?

//

 

[stolbovoy]

Get 4 of these: https://www.minidsp.com/products/opendrc-series/opendrc-di

and 2 of these: White Mini Portable SPDIF Toslink Digital Optical Audio 1 x 3 Splitter | eBay

?

//

1) Doesn't accept external master clock
2) No ASRC bypass
3) No native 192kHz support.

 

[TNT]

1) Doesn't accept external master clock
2) No ASRC bypass
3) No native 192kHz support.

1) If all units are fed the same spdif signal over toslink and the units themselves are not random generators, their frame synchronicity should be enough to create a stable stereo image - no?

2) Truncation/calculation errors audible?

3) Do we really need 192?

//

 

[stolbovoy]

1) If all units are fed the same spdif signal over toslink and the units themselves are not random generators, their frame synchronicity should be enough to create a stable stereo image - no?

2) Truncation/calculation errors audible?

3) Do we really need 192?

//

1,2) It is not about stereo image, but yes if there are different clocks my tweeter may be ahead or behind of mid-range due to ASRC. Probably not by a lot, but still can. Spending considerable amount of efforts to clock everything from one clock source (DAC) it sounds less then optimal solution.
3) If DAC itself is NOS than 192 is better. And also - why not? If my PC can do it without an effort, why should I us inferior solution that will cost me $1300 more?

 

[CharlieLaub]

1,2) It is not about stereo image, but yes if there are different clocks my tweeter may be ahead or behind of mid-range due to ASRC. Probably not by a lot, but still can. Spending considerable amount of efforts to clock everything from one clock source (DAC) it sounds less then optimal solution.
3) If DAC itself is NOS than 192 is better. And also - why not? If my PC can do it without an effort, why should I us inferior solution that will cost me $1300 more?

Audio at 192kHz is NOT superior in any way to audio in other sample rates.

 

[stolbovoy]

Audio at 192kHz is NOT superior in any way to audio in other sample rates.

Hm... In NOS DAC? No sin(x)/x frequency response shaping?
Also ovesampling DACs filters with constant # of taps sound a bit differently as the transients (ringing) has the same length in samples, but different in the real time

 

[CharlieLaub]

Hm... In NOS DAC? No sin(x)/x frequency response shaping?
Also ovesampling DACs filters with constant # of taps sound a bit differently as the transients (ringing) has the same length in samples, but different in the real time

All of those things have to do with the processing of the sampled audio, not the audio itself.