Crackling S/PDIF audio with H2+/Banana PI M2 Zero

kmi71 · January 28, 2025 at 10:07 PM

Hi,

running LE12 here on a Banana Pi M2 Zero with a cheap DAC (https://www.pollin.de/p/goobay-digit…-192-khz-631458) there are frequent background clicks, pops and crackles while playing audio in Kodi, but also while playing some .wav file with aplay.

With a recent Armbian image on the very same hardware, ALSA output is clean.

Any idea how to get rid of the noise or how to start debugging?

**Da Flex** · January 28, 2025 at 10:27 PM

Crackling is a common result of interrupted audio streams. This is often caused by a lack of processing speed. You can:

a) try to overclock

b) try to increase the audio buffer

I'm no Banana Pi expert, so I'm not sure whether a) or b) is possible.

**chewitt** · January 29, 2025 at 6:01 AM

Install the multimedia tools add-on and user alsamixer from the SSH console to reduce output volume. Pops and Clicks are normally the result of signals being overdriven.

**Da Flex** · January 29, 2025 at 8:26 AM

The user should hear the difference. Is it randomly, or is it clipping on peaks.

kmi71 · January 29, 2025 at 9:38 PM

Thanks, will look at the audio buffer size.

- processing power does not seem to be the bottleneck: running 20 gzip /dev/urandom in the background makes no audible difference
- it's not clipping on peaks, and it is audible when Kodi is idle, too (see attached "silence" recording)