Who is doing Linux / DSP / multi-amplification (multi channel) ?

[arvidb]

By the way, some projects piled ahaead of this project form me. I just bought Neumann KH80 and a SVS subwoofer. As of today, the subwoofer is doing the filtering but later I would like to go multichannel USB. 1) build speaker stands 2) tune the system with REW 3) finish some PhiDaCs I have since years (https://hackaday.io/project/27001-audiophile-sounding-dac-for-almost-no-money and DIYaudio) 4) build the multi USB2I2S interface....

I've been able to fit in a couple of sessions of work on my version. I seem to have a working driver for my codec now (pcm5242) including working volume control using a pot connected to the ADC on the STM32 board. (The on-board ADC was very noisy so this required both filtering and hysteresis to avoid volume "hunting".) I'm just testing this with a hard-coded sine wave for now.

I think I've also managed to integrate TinyUSB into the CubeMX-generated project so that at least everything compiles. I haven't had time to look at setting up TinyUSB correctly though (USB descriptors and such), so completely untested so far...

 

[jmf11]

Thanks for sharig arvidb,

Sure that is TinyUSB is doing the job, that would solve the license issue. I hope you will succeed.

JMF

 

[Musty]

Sounds kind of similar to the stuff people created with FreeDSP. Personally I would love a FreeDSP Aurora, but it seems like they stopped making them a couple of years ago. Currently on the hunt for a moderately priced USB 8 channel DAC with DSP (for a Linux computer ofc).

Regarding the license it's a bit strangely worded, but IMO "any manner that would subject this software to any Open Source Terms" definitely sounds like "you're not allowed to re-license our code".

No idea if this is close to what you wanted. I guess it's a rip-off of the mini DSP product rather than the original. I wondered if there was a usb-i2s bridge it would work with.

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[Musty]

I've been able to fit in a couple of sessions of work on my version. I seem to have a working driver for my codec now (pcm5242) including working volume control using a pot connected to the ADC on the STM32 board. (The on-board ADC was very noisy so this required both filtering and hysteresis to avoid volume "hunting".) I'm just testing this with a hard-coded sine wave for now.

I think I've also managed to integrate TinyUSB into the CubeMX-generated project so that at least everything compiles. I haven't had time to look at setting up TinyUSB correctly though (USB descriptors and such), so completely untested so far...

With all the ADC/DAC/i2c functionality one would think that esp32 should be good for the job but I can't find any implementation using it.

Inter-IC Sound (I2S) - ESP32 - — ESP-IDF Programming Guide latest documentation

 

[jmf11]

I've been able to fit in a couple of sessions of work on my version. I seem to have a working driver for my codec now (pcm5242) including working volume control using a pot connected to the ADC on the STM32 board. (The on-board ADC was very noisy so this required both filtering and hysteresis to avoid volume "hunting".) I'm just testing this with a hard-coded sine wave for now.

I think I've also managed to integrate TinyUSB into the CubeMX-generated project so that at least everything compiles. I haven't had time to look at setting up TinyUSB correctly though (USB descriptors and such), so completely untested so far...

Hi Arvidb,

Dit you progressed with TinyUsb stack? I'm now ready to resume on that project: speakers and subwoofer in operation. And I have finished by second DAC. So now ready to program stm32 for multi channel I2S, starting from a stm32 F4 discovery board.

Jmf

 

[MCH]

Hi Arvidb,

Dit you progressed with TinyUsb stack? I'm now ready to resume on that project: speakers and subwoofer in operation. And I have finished by second DAC. So now ready to program stm32 for multi channel I2S, starting from a stm32 F4 discovery board.

Jmf

Looking forward to reading about your progress.

btw, I can't believe there aren't any available working examples/projects of USB to TDM or multiple i2s without the DSP part, just the interface. I see people claiming to be working on stm32 based, rp2040 based, teensy based projects but can't find anything finished...

 

[jmf11]

Looking forward to reading about your progress.

btw, I can't believe there aren't any available working examples/projects of USB to TDM or multiple i2s without the DSP part, just the interface. I see people claiming to be working on stm32 based, rp2040 based, teensy based projects but can't find anything finished...

Same here. The USB multichannel thing seems to really be a niche, except for musicians (Motu, Focusrite...). Let's see if we can build something and share it... On the paper, 8 channels 48kHz, 16 or 24 bits seems achievable with UAC1. Maybe a simple extension of stereo examples may work.

JMF

 

[MCH]

one more interesting board. Seems to be ca. 75$ in alibaba (cannot find it anywhere else) and the software can be downloaded from the website (did not try)

PXUA-XU316-KIT硬件使用 | 木瓜电子开发文档

PXUA-XU316-KIT硬件使用，用于介绍PXUA-XU316-KIT评估板的硬件参数，应用场景，性能和功能，协助用户第一次使用PXUA-XU316-KIT进行项目评估，和如何DFU更新固件，以及如何在windows上使用该评估板。

docs.pawpaw.ltd

 

[jmf11]

one more interesting board. Seems to be ca. 75$ in alibaba (cannot find it anywhere else) and the software can be downloaded from the website (did not try)

PXUA-XU316-KIT硬件使用 | 木瓜电子开发文档

PXUA-XU316-KIT硬件使用，用于介绍PXUA-XU316-KIT评估板的硬件参数，应用场景，性能和功能，协助用户第一次使用PXUA-XU316-KIT进行项目评估，和如何DFU更新固件，以及如何在windows上使用该评估板。

docs.pawpaw.ltd

As I don't read chinese, it is difficult for me to confirm if it manages multichannels and how.

However, my game is to explore the stm32 way. Let's see...

 

[arvidb]

Hi Arvidb,

Dit you progressed with TinyUsb stack? I'm now ready to resume on that project: speakers and subwoofer in operation. And I have finished by second DAC. So now ready to program stm32 for multi channel I2S, starting from a stm32 F4 discovery board.

Jmf

Hi, sorry for the late reply; for some reason I didn't get an email notification about your reply even though I'm subscribed to this thread.

Anyway: I haven't had the opportunity to work any more on this. I did get it to compile before though and can give some pointers:

• Do not assign any USB-related pins in CubeMX. This will pull in STM32's USB code which will interfere with TinyUSB - and also taint the project with STM's unfriendly licenses.
• Don't include the whole TinyUSB code tree in CubeMX; the STM32's are supported by two drivers: the older "synopsys" one and the new "dwc2" one. If you include the whole tree you will get compiler errors about multiple definitions. Make sure to only include the dwc2 one.

Interested to hear about your experiences with TinyUSB!

 

[jmf11]

Thanks for your feedback. On my side, my intention is to start first with the ST UAC1 stack, ans see how I can go. But I could not dedicate much time to this up to now :-(

 

[Nutul]

I just came across this thread. Not a final product yet, but looks promising.

Introduction to the SmartCross project

Many of us are fascinated by the idea that we can process audio signals precisely and flexibly in the digital domain. Currently, there are numerous options available in the market, including popular offerings like MiniDSP and FusionAMP, each with their unique aspects. People have also brewed...

www.audiosciencereview.com

 

[MCH]

I just came across this thread. Not a final product yet, but looks promising.

Introduction to the SmartCross project

Many of us are fascinated by the idea that we can process audio signals precisely and flexibly in the digital domain. Currently, there are numerous options available in the market, including popular offerings like MiniDSP and FusionAMP, each with their unique aspects. People have also brewed...

www.audiosciencereview.com

Interesting, but 2 channels input only "for the moment". I still hope @jmf11 and @arvidb get it sorted out first.

 

[jmf11]

Not progressing much, but still near the top of the hobies todo list. I want to experiment a basic but still usefull configuration: based on a stm32, and the official stm32 UAC1 stack, try to achieve 6 or 8 channels USB to I2S.

From a Xmos paper, USB FS and UAC1 should allow 8 channels 44.1/48kHz - 16 bits.

I will use a previous revision of https://www.st.com/en/evaluation-tools/stm32f4discovery.html

JMF

 

[Jukka]

A few years ago I was looking for something like that. I needed 4 channels. I went for miniDSP SHD, because no real alternatives are to be found.

Right now I'm looking for the same, but with just 2 channels, usb input and small enough to sit on my computer desktop. Guess what? Nobody invented it, I need to get a miniDSP 2x4 HD and a separate chipamp. There is one alternative, but their DSP is closed software and I would need to buy the license multiple times to use it as I need to, so I'd rather pay for a something that's guaranteed to be good.

If you got suggestions, I'm open. I need to reread this thread though..

 

[Nutul]

A few years ago I was looking for something like that. I needed 4 channels. I went for miniDSP SHD, because no real alternatives are to be found.

Right now I'm looking for the same, but with just 2 channels, usb input and small enough to sit on my computer desktop. Guess what? Nobody invented it, I need to get a miniDSP 2x4 HD and a separate chipamp. There is one alternative, but their DSP is closed software and I would need to buy the license multiple times to use it as I need to, so I'd rather pay for a something that's guaranteed to be good.

If you got suggestions, I'm open. I need to reread this thread though..

Wat? A Raspberry Pi + Camilla can do 2ch DSP with zero hassle. Small footprint 3 x 2 x 1.5 inches, IIRC.
And it costs you the HW, as the rest is free.

 

[Jukka]

Wat? A Raspberry Pi + Camilla can do 2ch DSP with zero hassle. Small footprint 3 x 2 x 1.5 inches, IIRC.
And it costs you the HW, as the rest is free.

I hope you're correct on that one. It's just that looking at the hundreds of lines of text and configuration code in "how to CamillaDSP" threads turned me away quite quickly and I'm a pro software dev. Compared to miniDSP 1) unpack 2) plug in 3) listen, the cost of 50 more bucks becomes not-a-deal-breaker. When speaking of HW, I have an RPi4 and an unused usb-dac loitering around, but if looking at total cost of things, including power supplies and possibly more hats and whatnot, the cost of DIY can really get close to the miniDSP (which are on the more economical end of the devices). In this case the DIY solution might not be any better in performance, probably looks worse and is going to take more space.

Nevertheless I will try it. The speakers that I'm needing it for are also DIY, so I'm happy to try digital-electronics too.

 

[Nutul]

I hope you're correct on that one. It's just that looking at the hundreds of lines of text and configuration code in "how to CamillaDSP" threads turned me away quite quickly and I'm a pro software dev. Compared to miniDSP 1) unpack 2) plug in 3) listen, the cost of 50 more bucks becomes not-a-deal-breaker. When speaking of HW, I have an RPi4 and an unused usb-dac loitering around, but if looking at total cost of things, including power supplies and possibly more hats and whatnot, the cost of DIY can really get close to the miniDSP (which are on the more economical end of the devices). In this case the DIY solution might not be any better in performance, probably looks worse and is going to take more space.

Nevertheless I will try it. The speakers that I'm needing it for are also DIY, so I'm happy to try digital-electronics too.

I am a pro SW dev too, but it doesn't make me a Camilla-pro... ;-)
I just use it on moOde with a convolution filter for my active speakers and some PEQ for the room; I am not skilled / know all the bits of Camilla, but for what I use it, and what I needed to do / learn to have it working, I consider it a good tool at an excellent price, if used with a RPi.

I must say that my audio is read and played by the RPi, maybe this makes things a bit easier for me.

 

[jmf11]

Same here: I wanted CamillaDSP and went the moode route. Was easy to install and setup.

 

[Jukka]

What kind of hardware did you end up using? Do you have an addon board that handles power supply or do you feed with possibly with splitter cable? One of my requirements os usb input. I cannot use BT (like in JAB5 or KABD-4100), because it's got a ~500 ms sleep timer on Windows 10, which I cannot reliably disable. Stupidest thing ever for audio streams. I have got one miniamp that I could use, but if there are good addons or separates that don't require much work, I'm willing to try.