Re: [LAU] Midi sound Snafu - Linux-audio-user

25 Nov 2009

J. &lt;jonathangoodman(a)bezeqint.net&gt; wrote:

...
  Could anyone help me to get midi sound on a computer
that I'm setting up =
 for a freind woh has to use Linux and is not able to set up now by =
 himself?
 Problem (1): Before I upgraded to kubunyu 9.1 (from 9.0.?) I was able to =
 hear midi by playing the virtual keyboard; now it doesn' play.
 I have connected a usb midi controler and I see midi activity in =
 Rosegarden but no sound.
 What do I do.
 Problem (2): My friend told me how to set up a bash file (or whatever =
 it's called) to start Jack and it starts on the command line. But I'm a =
 command line dummy amd I can't type So I would like to know how to set =
 up Jack through ths jack controle graphically.=20
 And -could it be - that all the startup connection stuff on the graphic =
 controle has to do with the no-sound I get?

I am far from knowledgeable in the area of sound, but I had similar problems
on my laptop and here are my notes about how to resolve them. Whether they
apply to your friend's case is of course unknown. If there are any mistakes,
I'd appreciate corrections.

    I had problems getting sound out of rosegarden. I could get sound out
    of timidity through Jack.  I could get sound out of alsaplayer through
    jack. But rosegarden stayed resolutely silent.

    The problem was that for some reason, timidity was running as a system
    service (separate from any instances that I was running through jack).
    It gets started by /etc/init.d/timidity and it used ALSA as its output
    "device" (or whatever it is called - "device",
"channel", "port" are all
    overused). I killed that with /etc/init.d/timidity stop, although that
    is only a temporary solution.

    But Rosegarden does need a software MIDI synth to be running (at least on
    the laptop: there is no MIDI hardware on the motherboard). So the trick
    is to start jack first (with ALSA as its output device), then start timidity
    in the background with jack as its output device:

    /usr/bin/jackd -v -R -dalsa -dhw:0 -r44100 -p1024 -n3 -m -Xseq
    /usr/bin/timidity -Oj -iAD

    [Note that the audio system on my laptop *requires* 3 periods/buffer - the
    default 2 was causing a lot of scratchy noise.]

    Rosegarden can then be started and all is well.

I can also start vkeybd and have it connect to one of timidity's output
ports (obtained e.g.  from aconnect -o):

  vkeybd --octave 7 --addr 130:0

and it too is audible. Or you can connect the MIDI through-port to timidity's
output port (e.g. using qjackctl and the Connections menu) and then use

  vkeybd --octave 7 --addr 14:0

(where 14:0 is the MIDI through-port).

HTH,
Nick