4-channel DAC and DSP using Raspberry pi 5, CamillaDSP and Soekris DAM 1021

[nowonas]

Hi audio enthusiasts!

I'm embarking on a personal project to build a 4-channel DAC using two Soekris dam 1021 boards. This is more of a personal endeavor to explore DIY audio rather than a quest for superior sound. I'd love some advice and insights from those who have experience with similar setups.

Here's what I'm considering:

• Using 2 Soekris dam 1021 boards for a total of 4 channels
• Implementing I2S as the input interface
• Utilizing a Raspberry Pi 5 as the digital source
• Incorporating CamillaDSP for digital signal processing

I'm particularly interested in the I2S approach with the Raspberry Pi 5 as this seems to be a viable approach and does not need USB conversion

Some questions I have:

1. Has anyone successfully implemented a multi-board DAC setup using I2S from a Raspberry Pi with CamillaDSP?
2. Are there any specific challenges or considerations when using I2S with multiple DAC boards and CamillaDSP?
3. What's the best way to split the I2S signal for two separate DAC boards while maintaining compatibility with CamillaDSP?
4. Are there any recommended software solutions or distributions for managing a multi-channel setup on the Pi 5 that work well with CamillaDSP?
5. How can I effectively configure CamillaDSP for a 4-channel output using two separate DAC boards?

I'm open to all suggestions and would greatly appreciate any insights, tips, or warnings about potential pitfalls.

Thanks in advance for your help!

 

[HenrikEnquist]

The Pi 5 presents its i2s output as a single audio device with up to 8 channels. Seen from the software side, it doesn't matter what dac(s) the i2s is connected to. For example the hifiberry dac8x is basically 4 stereo dacs on a single board.

If you manage to configure the i2s output to work with the Soekris boards, then CamillaDSP should be able to use them just fine.
I don't know what signals those boards need. I think it's easy to get LR-clock and bitclock from a Pi5, but IIUC it should also be able to generate a master clock. But I don't think anyone has figured out how to make it do that yet.

 

[nowonas]

From my own investigations, handling of the master clock is a main concern when integrating the Soekris DAM1021 in this context.

The Soekris board can output a master clock signal of either 45.1584 MHz or 49.152 MHz. Further there's an I2S MCLK OUT pin for the master clock output. Given this information, does anybody know if it is possible to use this built-in master clock externally in this context? This could potentially solve synchronization issues when integrating the 2 different DAM1021 boards, and building multi-channel dac.

It's worth noting that while this master clock output capability exists, the DAM1021 itself doesn't require a master clock input for its I2S interface. It can sync to whatever signal it's fed, needing only serial data, word clock, and bit clock