Buzzing on GSM audio (settings also work well with GTA01)
eric at ericanddebbie.com
Sat Jul 26 19:12:21 CEST 2008
I spoke a little too soon. A real test talking to someone else still
had echo. So, it's better, but could still use improvement.
Eric Olson wrote:
> I'm just confirming that this helps audio on GTA01 as well. Testing
> with another phone, I was able to get rid of echo almost entirely
> (between our two phones) by reducing Mono Playback Volume to 72.
> Hopefully, this will be loud enough to hear well in noisy places -- I'll
> have to try that out.
> Here are the relevant numbers I settled on for now:
> (Tmobile US, other side was a cell phone, indoors -- not a noisy area)
> Mono Playback Volume 72
> Speaker Playback Volume 118
> Mic2 Capture Volume 3
> Mono Sidetone Playback Volume 7
> Bypass Playback Volume 7
> On another note, the headset seemed to work well just now unless the
> headset mic was brought near the other phone or was touching the usb
> cable near the neo. I didn't test it very long -- I'm sure there are
> other things that can cause interference. At least I could hear some of
> the buzz on the neo side, so I can at least test it in everyday use and
> tell if there's interference (instead of entirely relying on the other
> person to tell me there's a problem like I did with echo).
> Timo Jyrinki wrote:
>> 2008/7/26 Andrew Bruno <aeb at qnot.org>:
>>> FWIW, I've found tweaking these specific settings in
>>> /usr/share/openmoko/scenarios/gsmhandset.state effect the intensity of the
>>> buzzing sound. Specifically:
>>> * 'Mono Playback Volume' (85)
>>> * 'Mono Sidetone Playback Volume' (7)
>>> * 'Mic2 Capture Volume' (3)
>>> * 'Speaker Playback Volume' (112)
>>> * 'Bypass Playback Volume' (7)
>> Thanks! With these tweaks to my current settings, I've successfully
>> for the first time received a confirmation that the receiver of my
>> call didn't hear an echo of her own voice.
>> However, I did tweak "Mono Sidetone Playback Volume" from 7 to 4,
>> since in my own testings with two phones I heard quite a lot of buzz
>> still. That lessened it, and the receiver seemed to hear my well
>> enough anyway.
>> My paranoid / not-knowing-what-I-do procedure is to:
>> 1. change /usr/share/openmoko/scenarios/gsmhandset.state
>> 2. alsactl -f /usr/share/openmoko/scenarios/gsmhandset.state restore
>> 3. alsactl -f /etc/asound.state store
>> 4. reboot
>> I now added a link to your post at
>> since this is the first time I really achieved some good results.
>> support mailing list
>> support at lists.openmoko.org
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