[LAU] [Alsa-user] midi triggering delay

andy baxter andy at earthsong.free-online.co.uk
Sat Sep 19 11:42:34 EDT 2009


andy baxter wrote:
>
> The delay is variable - sometimes the note will sound almost 
> immediately, but usually there is a slight delay.
>
> I've tried with aseqdump, and as far as I can tell there is no delay - 
> 'note on' seems to appear at the same moment that I press the key.
>
> I've also tried using zynaddsubfx instead of qsynth / fluidsynth, and 
> the delay is still there.
>
> Which seems odd - I would have expected that if aseqdump was not showing 
> a delay then the problem must be with qsynth. Maybe there's some library 
> or code snippet that zyn and qsynth both share?
>
> I'm wondering if it would help to install the whole of ubuntu hardy on 
> my new laptop and see if that cures the problem (that's what my old 
> laptop is running, which works fine.)
>   

I've just tried this (installing hardy), and if anything the problem is 
worse. So it seems like some kind of hardware incompatibility. Somebody 
pointed out that the main difference between this machine and my old one 
is the dual core processor. I tried using schedtool to run jackd and 
qsynth on the same processor; this seemed to improve the situation 
slightly (though it's hard to tell as the delay is quite small and 
variable), but not enough that I can use this machine with the midi 
keyboard.

Would really appreciate some help with this from the developers if 
anyone can spare the time - I am happy to do any necessary diagnostic 
work at this end.

andy



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