29 Aug
2014
29 Aug
'14
8:01 p.m.
On Fri, 29 Aug 2014, Jonathan E Brickman wrote:
some careful experimentation; I am trying to build a
very dense Strings
instrument for my synth box ( http://lsn.ponderworthy.com ), and
although the 14-item LinuxSynth setup I have right now sounds great for
a second or two of note-hold, one hears increasing spits and pops and
static after more hold even on one note.
I was surprised that you include X and a wm at all. I would suggest
running screen from dbus-launch could do the same thing so long as all
your applications are CLI. I have set a box up this way and been able to
run pulseaudio, jackdbus and other things (before I ran out of memory on
the old P300). I would not suggest pulse in your case though. There are
some very good CLI tools for keeping track of jack connections.
It is relatively easy using sys v init, upstart or systemd to run a shell
script as a user that would start dbus and screen (or another cli session
manager) with a number of screens open and running some predefined
program. Ssh login to the box and type:
screen -df
will connect you to the already running screen instance running as your
user. I have done this from an android phone, though the text was really
too small :) but a tablet would be better. If you run out of buttons on
your keyboard, USB keyboards (qwerty) are cheap and the controller inside
can be directly connected to stomp switches. Actkbd can assign keypress to
CLI command or with the extension I am working on (it is far enough along
to be useful to you I think) send a jack midi command to your midi
filter/combiner or direct to an app.
There are also a number of MIDI control apps that send MIDI via
ethernet/wireless some of them for android. qmidinet should now be able to
run headless too.
Just a note and you may already know this, you can stack commands with
jack_control. For example I start jackdbus like this:
jack_control ds $DRIVER dps device $DEV dps rate $RATE dps period $FRAME \
dps nperiods $PERIOD start
From a script.
I understand using 96k for this project, but in the case of pops and such
have you tried setting 48k just to see if it goes away? Then setting
period 32 would give the same latency, but may still give cleaner sound.
You can use jack_bufsize to change period on the fly, but note that there
will be audiable artifacts and some applications (rakarrack for example)
never recover and need to be restarted.
--
Len Ovens
www.ovenwerks.net