[LAU] using Jack an interface to ecasound

[Joel Roth]

john gibby wrote:
> > Hi,
> > I'm having trouble setting up Jack to interface between my digital piano
> > application (pianoteq) and the ecasound audio processing app.  I'm using
> > ecasound with Ladspa plugins to create a crossover network.  Ecasound
> > splits the 2 pianoteq channels into six (woofer, mid & tweeter), and sends
> > them to my analog outputs through alsa. I have it working, with jack &
> > qjackctl, but the buffer size that jack is presenting to the digital piano
> > app is 1024, about 10x bigger than I want.  I would like pianoteq and
> > ecasound to run synchronously with minimal latency. At first  I thought I
> > could just call jackd  -d ecasound -p 128, but of course  ecasound is not
> > one of jack's supported backends.  So I've been using the "dummy" backend,
> > and using qjackctl to connect ports from pianoteq to ecasound.  That works
> > fine, but I can't manage to configure the buffer size down to 128, even
> > though I start up ecasound with -i jack -b:128

FWIW, from 'man ecasound':

Note that when any JACK input/outputs are used, the buffer
size  setting  is  overridden and set to period/buffer size
reported by JACK server (e.g. jackd’s ’-p’ option).  It is
not possible to turn off this behaviour.

> > , and I also go to setup in
> > qjackctl and specify buffer size 128 for "dummy".  When qjackctl brings up
> > the jack server, the buffer size gets overridden to 1024; I see the message
> > in the log. What am I doing wrong?  Is Jack the wrong approach, when it is
> > ecasound, not jack, that writes to alsa?

Ecasound can connect to both ALSA and JACK devices. I've
used that option in a setup using two soundcards. It is 
more common that jackd manages the soundcard. Do you have
any reason not to do so?

HTH,

Joel

> > Thanks very much!
> > John
> > Msi mb with i5 3ghz, AVS Linux
> >
> >
> >
> > --
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-- 
Joel Roth