18 Jan
2017
18 Jan
'17
2:46 a.m.
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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