Subject: Re: [linux-audio-user] soundfonts and samplers
From: Chris Cannam (cannam_AT_all-day-breakfast.com)
Date: Wed Aug 11 2004 - 22:48:30 EEST
On Wednesday 11 Aug 2004 8:30 pm, Iván Almada wrote:
> on the other hand ive realized specimen is a great
> sampler: everything i need (preview .wav, map
> different regions, loop point editor, filter, though
> more different filters would be very very nice...) and
> i didnt know you could use it directly from rosegardan
> through alsa midi , that excelent, just as if
> specimen was a plug in, i can trigger samples from my
> midi keyboard with an inperceptible latency, now i
> would like to know several more things, like how to
> apply ladpsa plugins to the sampler for example if i
> want to use some of the ladpsa filters...
The generic answer to "how do I add effects to this JACK app that
doesn't immediately appear to support them?" is to use jack-rack,
which is a very nice standalone JACK effects rack, hosting LADSPA
plugins. Run it up and then connect the output of your other JACK
app (Specimen in this case) into jack-rack using the qjackctl audio
connection manager.
(I can't remember offhand whether Specimen always outputs to JACK or
whether it also has direct ALSA output. You will obviously need to
have it outputting to JACK and have jackd running [via qjackctl for
example] to do this.)
> how is the
> audio routed from specimen back into the midi host
> mixer (it displays audio in a channel called rec... )
> but it has no slots for plug ins...
In this case the answer is that the audio is _not_ routed back into
the midi host. The only reason you see it on the Rec meter in
Rosegarden is because Rosegarden's record input is connected to the
soundcard capture channel, and that is receiving the same audio as is
being output to the speakers from Specimen. Even if you could apply
effects at that point in Rosegarden, it wouldn't alter the sound you
actually hear while playing.
Note that this also implies that if you record the results straight
back into Rosegarden as it stands, you'll get some noise because
you'll be recording the mixed soundcard input, not the pure output
from Specimen or jack-rack (I think). For a clean recording, you'd
have to use the same JACK connection manager to disconnect the
Rosegarden record input from the ALSA PCM in and reconnect it to the
output of Specimen or jack-rack or whatever.
Chris
This archive was generated by hypermail 2b28 : Wed Aug 11 2004 - 22:48:37 EEST