[alsa-devel] Fwd: Re: Alsa USB Audio regression

[Ulrich Günther]

-------- Original-Nachricht --------
Betreff: 	Re: [alsa-devel] Alsa USB Audio regression
Datum: 	Tue, 16 Jul 2013 18:27:10 +0200
Von: 	Ulrich Günther <ulrich.guenther at gmx.at>
An: 	Raymond Yau <superquad.vortex2 at gmail.com>



Am 2013-07-16 04:14, schrieb Raymond Yau:
>
>
> >>>
> >>> After Ubuntu 10.04 LTS (Ubuntu 10.10 works, Ubuntu 11.04 doesn't
> work at
> >>> all, Ubuntu 11.10 and newer have the bug), the headset only plays
> sound
> >>> at maximum volume level if the volume is turned down just a little no
> >>> sound is being played.
> >>>
> >>> I have filled a Ubuntu bug for 12.04 LTS at:
> >>> https://bugs.launchpad.net/ubuntu/+source/alsa-driver/+bug/1200925 .
> >>> I was advised to contact this mailing list.
> >>>
> >>> AlsaInfo for Ubuntu 12.04 LTS with the bug:
> >>>
> http://www.alsa-project.org/db/?f=3bde76b15a15f585418a6a4a4703ca67fd4cdf42
> .
> >>> AlsaInfo for Ubuntu 10.04 LTS without the bug:
> >>>
> http://www.alsa-project.org/db/?f=5824e55345c3f7128937405254485a489886b9dc 
> >>
> >>
> >>
> >> It is strange that dB range of your usb audio is 0 to 0.14 (only
> small gain and no attenuation)
> >>
> >> In 10.04 LTS pulseaudio provide software volume control
> >>
> >>
> >> ( 1.095| 0.000) I: alsa-sink.c: Driver does not support hardware
> volume control, falling back to software volume control.
> >>
> >>
> >> control.6 {
> >> comment.access 'read write'
> >> comment.type INTEGER
> >> comment.count 1 comment.range '0 - 37'
> >> comment.dbmin 0 comment.dbmax 14
> >> iface MIXER
> >> name 'Speaker Playback Volume' value 30 }
> >>
> >>
> >>  In 12.04 pulseaudio did not provide software volume attenuation
> and use the speaker playback volume control
> >
> >
> > So does that mean that the bug is in pulseaudio, or could it be even
> deeper like in the kernel or something?
>
> Are there any significant change in volume when you use "alsamixer
> -c0" to change speaker playback volume from min 0dB to 0.14dB ?
>
> Did pulseaudio provide software attuentation -1.61dB when the range of
> hardware volume control is only 0.14dB ?
>
> * index: 0
> name: <alsa_output.usb-0d8c_USB_Audio-00-Audio.analog-surround-71>
> driver: <module-alsa-card.c>
> flags: HARDWARE HW_MUTE_CTRL HW_VOLUME_CTRL DECIBEL_VOLUME LATENCY
> DYNAMIC_LATENCY
> state: SUSPENDED
> suspend cause: IDLE
> priority: 9049
> volume: 0:  94% 1:  94% 2:  94% 3:  94% 4:  94% 5:  94% 6:  94% 7:  94%
>         0: -1,61 dB 1: -1,61 dB 2: -1,61 dB 3: -1,61 dB 4: -1,61 dB 5:
> -1,61 dB 6: -1,61 dB 7: -1,61 dB
>         balance 0,00
> base volume:  99%
>              -0,14 dB
> volume steps: 65537
> muted: no
>
> It is strange that 5.1 headset only support 8 channels playback
>
Okay i did try "alsamixer -c0" in Ubuntu 12.04 LTS, i selected the Usb
Headset, Speaker was at 0 using the remote control from the headset i
could bring the value to 86, so if the volume is turned down the value
goes immideatly to 0.
With the alsamixer i was able to regulate the value between 0 and 100,
db-change is 0,01 at lowest and 0,14 at highest.
I could increment/decrement the db-change in steps of 0,01 (with the
up/down keys from the keyboard), the volume from the headset-speakers
follows accordingly.
When using anything besides the "alsamixer -c0" the volume can only be 0
or 86.
I was able to play the test sounds for: front center, front left, front
right, rear left,rear right and subwoofer every thing came from the
right direction, as expected from a 5.1 headset.
I was really surprised,  thank you for pointing this out, it really
didn't occur to me, maybe i saw the alsamixer some years ago but i
really couldn't remember that it was there.