Digital EQ idea: which USB audio adapter to capture SPDIF?

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evencrisper
Posts: 1
Joined: Fri Dec 11, 2015 6:36 pm

Digital EQ idea: which USB audio adapter to capture SPDIF?

Post by evencrisper »

Hello,

I want to build a DSP/digital EQ using a Raspberry Pi 2 and a USB audio interface. The idea is to have an optical signal come in to the Pi via SPDIF input, process the signal using an EQ plugin (e. g. alsaequal) and the output it again via SPDIF output.

I purchased a cheap USB audio card with both SPDIF in and SPDIF out. It had a C-Media CM6206 chip. However I could not for the life of me get capturing to work using ALSA/arecord. I only got an input/output error after around 10 seconds of trying to record, and an empty file. I tried very hard. Even recompiled the kernel with modified code (cm6206 snd-usb-audio quirk) to set the SPDIFMIX bit on that chip, but no luck.

I'm a daddy now, so I don't have time for this sh* :wink: So I would like to know: which USB audio adapter can be used with a recent kernel (4.3) using ALSA to record/capture the bytes from the SPDIF input?

Who has this (or a similar configuration) working? If so, please elaborate.

Thanks in advance for any help,
crisper
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