[SATLUG] Getting sound from MIDI

John D Choate jdchoate at gmail.com
Wed Dec 22 15:44:37 CST 2010


> Thanks for the suggestions: it turned out to be very helpful.
> 
> Since that reply, I have had some luck getting MIDI to work: thanks for the suggestions. I already had qsynth and jack installed,
> but wasn't sure if I needed sounfonts or not to play a midi file. I wonder: how does timidity do it?
> 
> I saw that Qsynth has the ability to load different sound fonts, so I looked around my system and found some in /usr/share/sounds/sf2. I
> loaded them, and started jack and qsynth. aplaymidi needs a port specified, but the -l option shows available ports: I saw 14:0 for "MIDI Through", 128:0-3 for Timidity, and, 
when Qsynth was running, 130:0 for qsynth. Just by trial and error, I found that when playing aplaymidi with the qsynth port (aplaymidi -p 130:0<midi file>), the activity light 
would light up in qsynth. Also, with verbose midi messages selected,
> a message saying "note on" would display: looked like something was happening, at least. Frequently this is how I progress: I poke around until something changes or 
happens, then proceed from there.
>    I happened to have the "Channels" input window open in Qsynth, and had double-clicked on channel 0, and noticed that it allowed the assignment of an instrument from a 
list. But still, nothing played. Then I had the channels window open when the file was playing, and noticed that the lights for channels 2 and 3 lit up. So I assigned an 
instrument to channels to and 3 (piano, in both cases), and then got
> sound. Eureka!
>    I proceeded from there to use something like this method with Rosegarden, except I found I didn't have to assign every instrument and channel: luckily, because some of 
those sample pieces in Rosegarden have maybe 12 parts. In Rosegarden, I had to select the "Manage MIDI Devices" icon, and choose, for MIDI Playback, the "Qsynth input port" 
(130:0).
>    Qsynth is set to use jack as the audio output driver. I see that "alsa" is also an option, and I may have tried it at one point, but I'm just reporting what is working for me at this 
time.
> 
> So far, so good. I see that the Linux Journal (http://www.linuxjournal.com/) has published some articles on Qsynth and seq24, and probably
> others. I saw a reference to Hammersound (http://www.hammersound.net/) as a source for sound fonts, but the ones I used were already on my
> system, in /usr/share/sounds.
> 
> Regards,
> 
> Frank Huddleston
> 
> 
> 

Good to hear of the progress. It's been a while since I tried a serious attempt at setting up MIDI, but I do remember the frustration of not having a soundfont installed and 
configured in qsynth. I also used to have a horrible time getting jack to work with my old sound card, Hercules Game Theater XP, and had to have qjackctl run jack in 'dummy' 
mode, instead of jackd.
I have yet to spend any real energy with jack and my new sound card, HT|Omega Claro Halo XT, but I do know that qjackctl can now start the actual jackd instead of 'dummy'... 
I think in realtime too. Will have to play with it more.

Happy Holidays,

John Choate


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