I finally got some spare time to "fix" my system. I installed arch linux from scratch (3.1 kernel) and the alsa drivers included there work way better than the ones included in ubuntu studio. The distortion is gone and the latency is decent (256 samples). Thanks for the input! :)

On Thu, Nov 3, 2011 at 7:33 AM, Rafael Vega <email.rafa@gmail.com> wrote:

Thanks for the input Daniel, I'll try this as soon as I reinstall my OS (messed up partitions :P)

On Nov 1, 2011, at 5:04 AM, Daniel James wrote:

> Hi Rafael,
>
>> My laptop is a MacBookPro8,1 with i7 processor, 8GB ram, built-in intel
>> HDA soundcard
>
> For Intel HDA a tweak is often required to get good performance. See:
>
> http://apps.linuxaudio.org/wiki/intel_hda_realtime_howto
>
> Ignore the kernel recompile part, but note the issue with mixer capture
> switches if using jackd in full duplex mode.
>
>> Codec: Cirrus Logic CS4206
>
> Try adding these options at the end of /etc/modprobe.d/alsa-base.conf
>
> options snd-hda-intel model=mbp55 position_fix=1 enable=1 index=0
>
> The mbp55 value for CS4206 is found near the end of:
>
> http://www.kernel.org/doc/Documentation/sound/alsa/HD-Audio-Models.txt
>
> Then reboot and see if JACK performance improves. You should be able to
> get 64 frames/period x 3 periods/buffer @ 48KHz on this hardware.
>
> Cheers!
>
> Daniel