Sometimes it seems ALSA on my machine goes completely haywire:
- Flash audio on Spotify doesn't produce any sound.
- SMplayer plays audio just fine, or doesn't play at all (I've observed the latter today).
- When I start a video in VLC it plays an extremely loud crack, so loud I'm afraid I'll lose hearing permanently and/or break a speaker. For comparison, I usually set the receiver volume to 25 when playing music, and 30-35 when watching movies. After detecting the previous two issues, I turned the volume to 6 before playing a video, and even then the crack was painfully loud.
- After the crack, the VLC audio stream is barely audible behind a wall of noise.
- I don't detect any extreme loudness, cracks or other distortion from
speaker-test --device plughw:1,0 --channels 2.
How can this issue affect only Flash and VLC, but not SMplayer? They all use ALSA and the same sound card, after all. And these symptoms are relatively rare - only detected once every couple weeks or so. A reboot seems to solve them every time, but I would rather have some sort of guarantee that my ears will continue working.
The machine is set up from bare bones Arch Linux, and had as far as I can tell only the ALSA sound server installed when the problems were encountered.
The S/PDIF cable is connected to an Onkyo receiver, which is connected to a 5.1 speaker system.