Can we fix the audio for A5/A6/A7?

joerg joerg.twinklephone at
Thu Apr 3 01:06:46 CEST 2008

Am Mi  2. April 2008 schrieb andrzej zaborowski:
> Hi,
> On 02/04/2008, joerg <joerg.twinklephone at> wrote:
> > Am Mi  2. April 2008 schrieb Werner Almesberger:
> >  And did anybody ever try to enjoy *music* via headphones/NEO, not just 
place a
> >  call?
> >  btw: Issue is common to GTA01 too. So any experience there with music /
> >  replacement headphones?
> I just tried listening to the same piece of music on my PC, on the
> GTA01 and the GTA02A4.  I used the same headphones also (cheap no
> brand but not very bad). There were no problems getting very high
> volume level on either PC or GTA01 (higher than my ears could take and
> higher than the headphones could take). There is a noticeable bass
> cut-off on my GTA01 and GTA02 compared to the PC btu very likely it's
> one of the mixer settings (that or a bass boost on the PC). 

That's exactly the expected symptom - no bass because of too small capacitors.
The volume probably is ok, it depends on your headphones, but usually you 
easily can damage your ears (like with every other "walkman").
The problem is: with common 32Ohm-headphones, there is a cutoff frequency of 
~2500Hz, and lower frequencies are -3dB (half volume) for every octave, that 
is 1250Hz:-6dB  600Hz:-9dB  300Hz:-12dB...
It's no issue of the adapter, mixer settings (there aren't any!), etc...
Just 1uF capacitor.
Many thanks for the report! :-)


More information about the openmoko-kernel mailing list