Volume levels in mixer are not correctly defined

Bug #42043 reported by jalonsom
12
Affects Status Importance Assigned to Milestone
alsa-utils (Ubuntu)
Invalid
Undecided
Unassigned
gnome-alsamixer (Ubuntu)
Invalid
Medium
Unassigned
linux (Ubuntu)
Expired
Undecided
Unassigned

Bug Description

Alsa mixer in Dapper Beta:

This bug could make a user think that sound is broken.

- Choose an audio file with high volume (any modern track that is normalized will do) and play it, in a loud part.
- Open mixer
- Set PCM to 80% and Master to 100%. Sound is OK
- Set PCM to 100% and Master to 80%. Sound is distorted.

Conclusions:
- PCM and Master volume values mean different things. Not a good idea.
- Master volume values seem OK.
- PCM current value "80%" should correspond to "100%", because above this point clipping occurs with normalized files. Maybe it is not exactly 80%, but very close.
- Values above this point are useful to deal with audio files with low volume, but should be marked >100% to reflect that clipping may occur.
- Maybe Values above 100% should be considered for Master also.
- There should be something in the mixer that indicates clearly that we are above 100% volume (a line, or maybe changing slider color to red)
- Numerical values for volume should be shown in mixer window, as they are shown in volume applet in taskbar, or permanently.

Some of this things may apply to input volumes.

Revision history for this message
Anthony DeChiaro (adechiaro) wrote :

I've been experiencing this problem too for a *long* time now, ever since Breezy IIRC. I came across the solution the parent suggested, but it would be nice to see a permanent solution or even a 'fixed' hack to resolve this. People on the Ubuntu forums suggested you can get the 'max' value for PCM volume in a configuration file... currently looking into it. This may not be an issue for most, but for people who have high quality home theater soundsystems hooked up to Ubuntu might not be too happy.

Revision history for this message
Manuel López-Ibáñez (manuellopezibanez) wrote :

If the same happens with alsamixer then it is a bug in alsa-utils package, similar to bug 16454.

It will affect all ubuntu distributions: Kubuntu, etc.

Revision history for this message
Ashton Batty (ashton) wrote :

Same thing happens in alsamixer for me.
Alsamixer shows that the PCM channel at 74 has "dB gain=0.00, 0.00". Setting PCM above 74 increases the dB gain above 0, and results in distortion.

Revision history for this message
Daniel T Chen (crimsun) wrote :

Not an alsa-utils or a gnome-alsamixer issue.

Changed in gnome-alsamixer:
status: New → Invalid
Changed in alsa-utils:
status: New → Invalid
Revision history for this message
Leann Ogasawara (leannogasawara) wrote :

The Ubuntu Kernel Team is planning to move to the 2.6.27 kernel for the upcoming Intrepid Ibex 8.10 release. As a result, the kernel team would appreciate it if you could please test this newer 2.6.27 Ubuntu kernel. There are one of two ways you should be able to test:

1) If you are comfortable installing packages on your own, the linux-image-2.6.27-* package is currently available for you to install and test.

--or--

2) The upcoming Alpha5 for Intrepid Ibex 8.10 will contain this newer 2.6.27 Ubuntu kernel. Alpha5 is set to be released Thursday Sept 4. Please watch http://www.ubuntu.com/testing for Alpha5 to be announced. You should then be able to test via a LiveCD.

Please let us know immediately if this newer 2.6.27 kernel resolves the bug reported here or if the issue remains. More importantly, please open a new bug report for each new bug/regression introduced by the 2.6.27 kernel and tag the bug report with 'linux-2.6.27'. Also, please specifically note if the issue does or does not appear in the 2.6.26 kernel. Thanks again, we really appreicate your help and feedback.

Revision history for this message
kernel-janitor (kernel-janitor) wrote :

Hi jalonsom,

This bug was reported a while ago and there hasn't been any activity in it recently. We were wondering if this is still an issue? Can you try with the latest development release of Ubuntu? ISO CD images are available from http://cdimage.ubuntu.com/releases/ .

If it remains an issue, could you run the following command from a Terminal (Applications->Accessories->Terminal). It will automatically gather and attach updated debug information to this report.

apport-collect -p linux-image-`uname -r` 42043

Also, if you could test the latest upstream kernel available that would be great. It will allow additional upstream developers to examine the issue. Refer to https://wiki.ubuntu.com/KernelMainlineBuilds . Once you've tested the upstream kernel, please remove the 'needs-upstream-testing' tag. This can be done by clicking on the yellow pencil icon next to the tag located at the bottom of the bug description and deleting the 'needs-upstream-testing' text. Please let us know your results.

Thanks in advance.

[This is an automated message. Apologies if it has reached you inappropriately; please just reply to this message indicating so.]

tags: added: kernel-sound
tags: added: needs-kernel-logs
tags: added: needs-upstream-testing
tags: added: kj-triage
Changed in linux (Ubuntu):
status: New → Incomplete
Revision history for this message
Jeremy Foshee (jeremyfoshee) wrote :

This bug report was marked as Incomplete and has not had any updated comments for quite some time. As a result this bug is being closed. Please reopen if this is still an issue in the current Ubuntu release http://www.ubuntu.com/getubuntu/download . Also, please be sure to provide any requested information that may have been missing. To reopen the bug, click on the current status under the Status column and change the status back to "New". Thanks.

[This is an automated message. Apologies if it has reached you inappropriately; please just reply to this message indicating so.]

tags: added: kj-expired
Changed in linux (Ubuntu):
status: Incomplete → Expired
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