[LAU] Jack vs. Alsa, PianoTeq demo: Alsa wins!

[Paul Davis]

On Sun, Jun 12, 2011 at 3:40 AM, Aaron Krister Johnson
<aaron at akjmusic.com> wrote:
> Hi all--
> I'm wondering if anyone else has experienced this:
> I'm considering purchasing PianoTeq, but I wanted to try the demo. It seems
> to work better with just the alsa driver than it does with jack, a reversal
> of the usual situation.
> I tested this several times by playing fast glissandi on the default piano
> preset. Each time, my little EEE-PC netbook under jack choked with xruns and
> a brief silence while PianoTeq 'reset' itself, but Alsa alone chugged away
> with no xruns unless there was an extreme amount of load....
> I'm wondering if anyone can comment on this. It seems odd, especially since
> the jack developers claim jack adds no latency by itself to the picture in
> any situation---so, do we have a situation where the code is better written
> for the alsa driver than for jackd? It seems we do, in this case....

you should check the latency that it is using with ALSA. Assuming you
use the first audio device on the first sound card:

   cat /proc/asound/card0/pcm0p/sub0/hw_params

and then compare that with your JACK settings.

--p