On Sun, Feb 21, 2010 at 10:35:25PM +0100, Jan Stary wrote: > > > record.adc-0:1_mute=off > > > record.adc-0:1=224,224 > > > > that is amplifying the input to the ADC considerably. the 0..255 mixer > > values represet -16.5..+30dB *for this codec*. it would be nice if > > mixer values corresponded to decibles somehow, but that is not the case > > currently. > > > > > inputs.mic=85,85 > > > > this is the mic pre-amp. *for this codec*, the values are 0, 10, 20, 30 > > dB. > > > > you'll probably have better results using more mic preamp and not > > amplifying the ADC input signal. > > > > > outputs.mic_dir=input-vr100 > > > > here you have the mic jack using 100% AVDD (5.0V). unlikely to change > > anything, but you might want to try input-vr50 and input-vr80. > > The mixer settings above are a result of experiencing with > various combinations of more/less of preamp/mic-in/adc. > > All the combinations I tried showed the DC offset, > but this one sounded "best": with more mic preamp > and less ADC input, or with less input-vr and more > ADC input, the amount of noise was untolerable. > > I will play with them some more. > Thanks for the details!
if all else fails, here's a port for swh-plugins, a set of LADSPA modules. it has a dc offset remover. it can be used with audacity, or any application that can use LADSPA plugins. http://jakemsr.trancell.org/swh-plugins-0.4.15-port.tgz > (If mixer values corresponded to decibels, > that would be really good.) http://marc.info/?l=openbsd-tech&m=123101323408867&w=2 -- [email protected] SDF Public Access UNIX System - http://sdf.lonestar.org
