Bug 518512 - Having different streams output at different volume adds noise to output
Summary: Having different streams output at different volume adds noise to output
Alias: None
Product: Fedora
Classification: Fedora
Component: pulseaudio
Version: 11
Hardware: All
OS: Linux
Target Milestone: ---
Assignee: Lennart Poettering
QA Contact: Fedora Extras Quality Assurance
Depends On:
TreeView+ depends on / blocked
Reported: 2009-08-20 16:32 UTC by Amit Shah
Modified: 2010-06-28 14:12 UTC (History)
5 users (show)

Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Clone Of:
Last Closed: 2010-06-28 14:12:12 UTC
Type: ---

Attachments (Terms of Use)

Description Amit Shah 2009-08-20 16:32:23 UTC
1. I have rhythmbox playing some music
2. Have another source of audio, I had centerim that outputs some beeps when I receive messages
3. In the sound preferences dialog, increase the volume that gets output for the centerim beep events
4. Some noise gets added to the music playing when a beep is emitted.

The beeps are of a really short duration and the noise is added when the beep starts as well when it ends.

Comment 1 Lennart Poettering 2009-08-24 02:38:15 UTC
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?

Comment 2 Amit Shah 2009-08-25 12:46:37 UTC
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

Comment 3 Amit Shah 2009-09-15 08:42:29 UTC
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.

Comment 4 Lennart Poettering 2009-10-26 19:28:00 UTC
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?

Comment 5 Amit Shah 2009-10-27 09:26:12 UTC
I doubt that; but do you want me to try any debug build(s)?

Comment 6 Amit Shah 2009-11-05 09:21:24 UTC
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.

Comment 7 Adam Williamson 2009-12-02 20:19:44 UTC
This forum thread seems similar:


Fedora Bugzappers volunteer triage team

Comment 8 Bug Zapper 2010-04-28 09:51:37 UTC
This message is a reminder that Fedora 11 is nearing its end of life.
Approximately 30 (thirty) days from now Fedora will stop maintaining
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Comment 9 Bug Zapper 2010-06-28 14:12:12 UTC
Fedora 11 changed to end-of-life (EOL) status on 2010-06-25. Fedora 11 is 
no longer maintained, which means that it will not receive any further 
security or bug fix updates. As a result we are closing this bug.

If you can reproduce this bug against a currently maintained version of 
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