Experiment: better sound on remote end

rms at 1407.org rms at 1407.org
Wed Dec 2 14:47:44 CET 2009


Experiment: better sound on remote end
http://blog.1407.org/2009/12/02/experiment-better-sound-on-remote-end/

One of the problems people complain about my calls from the Freerunner is *bad*sound*.
Lot's of background noise, static, etc. I'm not talking about the familiar buzz problem,
as I've had the buzz fix applied to my phone.

http://picasaweb.google.com/RuiMSeabra/DebConf9OpenMokoBuzzFixParty#

However what I found to fix this problem on
my phone model (GTA02v5 + buzz fix) goes totally against the official information.

http://wiki.openmoko.org/wiki/Neo_Freerunner_audio_subsystem#Alsamixer_channel_controls

So much so that there's at least one person who, from his very good knowledge about this
subject (Really! This is *not* sarcasm!), thinks this fix is as good as putting some peanut
butter over the microphone :)

http://wiki.openmoko.org/index.php?title=Talk:Neo_Freerunner_audio_subsystem&oldid=77886

I know of at least one other person who claims to have better sound on remote end from this fix,
but I think I need to drop the challenge. Can you try the current SHR Unstable, apply this fix
and then report on the mailing lists your results?

You can? Good! So here's the fix:

	1. call someone who noticed your bad sound and check whether the sound is still bad, then
           finish the call
	2. edit /etc/freesmartphone/alsa/default/gsmhandset
	3. change control 63 (it's also on line 63), so that it ends in 3 rather than in 2:
	 * Old value: 63:'Mic Sidetone Mux':1:2
	 * New value: 63:'Mic Sidetone Mux':1:3
	4. call that person again and check the result

Alternatively, in one call, you can ssh into your phone and use alsamixer to change the same
control, but this change will not be persistent until you do the steps above.

http://blog.1407.org/wp-content/uploads/2009/12/oldValue.png

http://blog.1407.org/wp-content/uploads/2009/12/newValue.png

So let's hear your results, nothing like a good empirical experiment.

In the following recordings (complete set here),

http://files.1407.org/openmoko/mic_sidemux_test/

I said «The quick brown fox jumps over the lazy dog» starting with Mic2, then Right PGA, then Left PGA.

	1. in perfect conditions;
           http://files.1407.org/openmoko/mic_sidemux_test/test1-perfect-conditions.wav
	2. with tv making background noise (news);
           http://files.1407.org/openmoko/mic_sidemux_test/test2-with-tv.wav
	3. 2. + computer playing loud music («Te Quiero Puta» from Rammstein) at the same time.
           http://files.1407.org/openmoko/mic_sidemux_test/test3-with-tv-and-music.wav



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