stream and master volume below 50% mutes audio

[brian_j_murrell]

I'm using pulseaudio 0.9.10 on an:

00:10.1 Audio device: nVidia Corporation MCP51 High Definition Audio (rev a2)

but I have noticed a strange artifact.

If I put the volume for an application stream at "50%" (i.e. -15db) and then set the master volume at 50% or lower, the sound actually mutes. If I keep the stream at 0db, I'm then able to enjoy the use of the master volume through it's entire range.

The inverse is also true. If I have the master volume at 50%, when stream is at -15db or lower, it mutes completely. If I have the master volume at 100%, then I can enjoy the full range of volume on the stream.

It seems like the stream volumes and the master volume are being "additive" rather than, hrm, what would I call it? Maybe multiplicative is the right term. Perhaps. Anyway, I think you get the picture.

Interestingly enough, I found one other complaint about this at http://fixunix.com/ubuntu/513334-pulseaudio-volume-control-issue.html

[lennart]

This is not really surprising. -15db at the stream level and (possibly) -15dB at the device level add up to -30dB (multiplying linear factors equals adding logarithmic factors) That relates to a linear factor of about .0009. At 16 bit samples this decreases the sample range to about < 64 levels.

Also note that PA 0.9.10 considered <= -30dB equal to -inf dB. In newer version this has been moved to -60 dB.

the link you posted doesn't work.

[brian_j_murrell]

Replying to lennart:

This is not really surprising. -15db at the stream level and (possibly) -15dB at the device level add up to -30dB (multiplying linear factors equals adding logarithmic factors) That relates to a linear factor of about .0009. At 16 bit samples this decreases the sample range to about < 64 levels.

Hrm. Well, that explanation is above my head, not being familiar with how audio actually works.

I just know that this is new behavior since switching from using an SB emu10k to this nVidia HDA controller. On the SB, I could reduce the volume of both the stream and the master in any combination of decrements and the sound would always just get lower and lower until reaching zero in accordance with the slider. Even a single increment above 0 on both sliders produced sound.

Now with this HDA controller, the sound drops off from quite audible to absolutely nothing when either slider is at "half" and the other is put at one decrement below half. It acts and sounds more like a mute than a volume drop. Indeed, I am unable to achieve a "quiet" volume with any combination of the two sliders. It's always "comfortable" to zilch with nothing between.

Also note that PA 0.9.10 considered <= -30dB equal to -inf dB. In newer version this has been moved to -60 dB.

Maybe this solves the problem. But given the difference in behavior in a single version based purely on the hardware, maybe not.

the link you posted doesn't work.

Yes, that appears to be the case. Pity.

Beyond being audibly unintuitive (sound dropping from "comfortable" to muted) it's visually unintuitive to have audio completely muted when both sliders are at any value other than zero. I cannot see how this can be not considered a bug which wont be fixed. That said, I will leave this ticket closed and defer to your decision to reopen or not.

[brian_j_murrell]

No comment on my new notes to this bug. It really is a bug, either in how the various volumes are handled or presented to the user.

Maybe I need to reopen in order for comments to be propagated. Will do so.

[brian_j_murrell]

So are my observations on the UI or functionality otherwise invalid simply because you don't agree?

Did you take a moment to read my new notes and understand how unintuitive the existing functionality is and how the problem as I describe it is unique to particular sound devices? i.e. this problem only exists with my HDA and didn't exist with my Sound Blaster EMU10K despite it's poor acceptance by the developers.

I don't know how you can say "all is working as it should be" when the UI functionality is different depending on the hardware being used.

[lennart]

We have replace the dB to % mapping in 0.9.16 which should make the volume sliders feel much more natural, so that a greater part of the sliders actually maps to hearable volumes.