Bug 518512

Hmm, this might be caused by the hw volume changes we do. Could you verify with "alsamixer -c0" that the hw volume is modified when you hear this?

Does this sound like an electric problem to you? I.e. some kind of artifact caused by the hw instead of the software?

Yes, the 'master' volume changes in the alsamixer output when this happens.

hm, I can't say whether this is hw- or sw- related. The static noise is for a short duration; it sounds like it's the same each time and not dependent on the audio that's playing; so it could be a hw-related artifact but I can't really say.

00:1b.0 Audio device: Intel Corporation 82801I (ICH9 Family) HD Audio Controller (rev 03)
	Subsystem: Lenovo Device 20f2
	Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR+ FastB2B- DisINTx-
	Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
	Latency: 0, Cache Line Size: 64 bytes
	Interrupt: pin B routed to IRQ 17
	Region 0: Memory at f2620000 (64-bit, non-prefetchable) [size=16K]
	Capabilities: <access denied>
	Kernel driver in use: HDA Intel
	Kernel modules: snd-hda-intel

I just noticed that something strange happens also when the sound is restored to the previous value.

That is:
- have music playing via rhythmbox
- have beeps from an app like centerim be emitted at a higher volume
- when the beep starts, there's some noise as described above. The gnome-panel volume applet shows volume go up one level higher
- when the beep is finished, there's a momentary muting of the output (music). This again happens precisely when the gnome-panel volume applet goes from the higher level to lower.

Could this noise by caused simply by clipping? i.e. if we sum two 16bit signals the result might actually leave the 16bit range. Could that be the problem here?

I doubt that; but do you want me to try any debug build(s)?

It could be a result of clipping -- when my audio output is soft, I don't hear the noise and when I do hear the noise, it always sounds the same.

This forum thread seems similar:

http://forums.fedoraforum.org/showthread.php?t=235505

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