Non linear volume in openSUSE

[suse_tpx60s]

Just wondering why the volume control is not linear. Compared to XP, the volume (loudness) doesn't increase or decrease linearly when moving the volume slider. All my volume is controlled within the top 30% of the volume slider.

Is this a general Linux / openSUSE thing or is it only my hardware that is doing this?

[oldcpu]

Originally Posted by suse_tpx60s

Just wondering why the volume control is not linear. Compared to XP, the volume (loudness) doesn't increase or decrease linearly when moving the volume slider. All my volume is controlled within the top 30% of the volume slider.

Is this a general Linux / openSUSE thing or is it only my hardware that is doing this?

My understanding is this is linux wide and not specific to openSUSE. ie. openSUSE does not implement any special "multimedia volume" controls but rather relies on generic kmix, alsamixer, etc ... that are common to all distributions.

As to whether winXP is more linear, I can't say, since I don't use it.

If you believe there is something wrong here, you could write a bug on alsa, or even on openSUSE, as I note an alsa developer also packages the alsa applications for openSUSE. Submitting Bug Reports - openSUSE ... so in essence while you are raising the bug report on openSUSE you will get the attention of a Linux alsa developer, who is very good at sending alsa patches upstream to benefit all Linux distributions.

oldcpu wrote:
> suse_tpx60s;2061422 Wrote:
>> All my volume is controlled within the top 30% of the
>> volume slider.
>
> My understanding is this is linux wide and not specific to openSUSE.

i do not know what suse_tpx60s is looking at when he notes the bottom
two thirds of his slider does nothing...and, i don't know what
(apparently) oldcpu is looking at, and agreeing such is true for all
of linux...

but, i have not noticed that at all here.

i'm using openSUSE 10.3 with KDE3.5.7 on a ASRock K8Upgrade-760GX
motherboard with built in CMedia 9761 6channel AC'97 audio, and when
using the built-in KDE3 "Sound Mixer" named KMix, on the Output tab i
have a slider named PCM (have NO idea what that means) but it smoothly
increases/decreases the volume from nothing to full, using the entire
scale to do so..

true, moving one scale mark in the top third yields a more relative
change than moving one scale mark in the lower third...which means it
is a log, rather than pure linear...but, the bottom two thirds is
*not* useless..

suggest maybe you need to increase the gain at the speaker amp itself,
if you have that capability..

--
palladium
Have a lot of fun..

[oldcpu]

Originally Posted by palladium

...and, i don't know what (apparently) oldcpu is looking at, and agreeing such is true for all of linux...

I thought I made that clear.

openSUSE uses generic Linux tools: kmix, alsamixer, alsa ... etc ... And when openSUSE developers/packagers have fixes, they pass them upstream for all Linux. That i what I am looking at. ok ?

[suse_tpx60s]

Originally Posted by palladium

oldcpu wrote:
> suse_tpx60s;2061422 Wrote:
>> All my volume is controlled within the top 30% of the
>> volume slider.
>
> My understanding is this is linux wide and not specific to openSUSE.

i do not know what suse_tpx60s is looking at when he notes the bottom
two thirds of his slider does nothing...and, i don't know what
(apparently) oldcpu is looking at, and agreeing such is true for all
of linux...

palladium
Have a lot of fun..

I'm referring to the Kmix volume slider. I have the PCM slider at 80%, any higher and I start to get distortion. If I then slide the master volume slider down I get no volume below ~60% and that is with the sound being fed into my AV amp with gain set correctly. If I listen through the laptop speakers I loose the volume below ~65%.

The strange thing is it I set the master at 100% then slide the PCM slider down the volume decreases in a linear fashion and I can still hear it right down to ~3%.

It seems the master volume isn't following a linear path which the PCM slider does. I wonder if this is by design or not. The reason I posted this was to find out if it was 1) openSUSE specific - which I now know it's not and 2) to see if it was perhaps my hardware causing this; and other users with different hardware don't experience this.

Oldcpu, do you experience the same non linear scale for the volume?

@palladium, so when you adjust your volume do you open the mixer to change the PCM slider or is that set to be the master volume controller on the volume icon on the panel? Did Kmix change much between KDE3.5 and KDE4?

[TaraIkeda]

Yes kmix changed quite a bit between kde 3 and 4, for me at least as I noted the slider settings are a little different.

[oldcpu]

Originally Posted by suse_tpx60s

Oldcpu, do you experience the same non linear scale for the volume?

On my laptops, yes. On my desktops, No.

[seld]

Originally Posted by oldcpu

On my laptops, yes. On my desktops, No.

Same on my systems.

Desktop's (Gigabyte GA-P35-DS3R) 'Master' volume slider has smooth volume adjustment.
Laptop's (Intel GM965) 'Master' volume slider has sort of a 'brake point', which is nearly in the center.

Before this point it is too quiet. Actually position does not seem to change sound significantly - It is almost the same if set to 40%, 20% or 0% - too quiet, but I can hear it through laptop speaker even at 0%.

After this 'break point' volume can be adjusted smoothly as it should be.

And with 'PCM' (whatever it is) slider I can adjust sound smoothly.
Hmm... I guess I should set 'Master channel' in Kmix from 'Master' to 'PCM' (which is really odd).

I don't remember how is it set in Windows Vista (I don't normally boot it), and whether Vista changes PCM or Master by default, but I can check it.

[suse_tpx60s]

Originally Posted by oldcpu

On my laptops, yes. On my desktops, No.

Originally Posted by Seld

Same on my systems.

Desktop's (Gigabyte GA-P35-DS3R) 'Master' volume slider has smooth volume adjustment.
Laptop's (Intel GM965) 'Master' volume slider has sort of a 'brake point', which is nearly in the center.

That's interesting, so it seems to be related to hardware and in particular laptops.

@Seld, how do you set the master channel from master to pcm in Kmix? I don't see a setting for that. Is it a code hack?

Also, for me the pcm channel increases the gain so much that anything above 80% induces distortion at any given master volume level? Does that happen on desktops too?

I just checked in XP and there is no PCM channel but all the channels available in XP operate in a linear fashion.

Do you think it would be worth starting a poll to see which configurations have this non linear volume characteristic? I can then use the data to file a bug report.

[oldcpu]

Originally Posted by suse_tpx60s

Do you think it would be worth starting a poll to see which configurations have this non linear volume characteristic? I can then use the data to file a bug report.

A difficulty with polls related to Linux audio hardware and associated software is there are so many different configurations. Some mixers with some hardware will have Master volume, PCM volume, and a Speaker Volume. Others will have only Master volume and PCM volume. And a small minority will have the additional surround controls associated with 2.1 or 4.1 or 5.1 ... systems.

I've noted many laptop's mixer's do not have a linear scale, but that may be due to the laptop's hardware audio codec implementation.

Even with the same hardware, what an openSUSE-10.3 user will see in their KDE3 (or Gnome) mixer compared to an openSUSE-11.1 user in their KDE4 (or Gnome) mixer may be different due to changes made in alsa-1.0.14 (on 10.3) to alsa-1.0.18 (on 11.1).

Still you could create such a poll, but I'm thinking the most you can get out of it is a very general broadbased indication of how many suffer from a non-linearity in their mixer.