[LAU] Status of lisalo/lisaloQt and calfbox?

[Len Ovens]

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