[LAD] Tests directly routing pc's midi-in to midi-out (was: Re: ALSA MIDI latency test results are far away from reality)

[Arnout Engelen]

On Wed, Jul 14, 2010 at 11:54:35PM +0200, Ralf Mardorf wrote:
> On Wed, 2010-07-14 at 23:43 +0200, fons at kokkinizita.net wrote:
> > On Wed, Jul 14, 2010 at 11:28:54PM +0200, Ralf Mardorf wrote:
> > > Or it was at 4 ms = +- 2ms or something like that. This is a delay that
> > > isn't audible for day-today-day audio events, but it can brake a groove
> > > easily.

That would mean my hardware synth (the yamaha vl70-m), connected *directly* 
(no PC involved), causes a huge latency (20-26ms) making it utterly unusable 
for making a groove - and not just slightly, but by a large margin.

That *could* be (as it's not a drum synth), but it'd be kind of surprising. 

> > You keep repeating this, but so far I haven't seen a shred
> > of verifyable evidence to support this claim.
> 
> I could record audio for kick, snare, hi hat and bass one after the
> other and mix it to one rhythm group and additionally I could record all
> instruments at the same time and send the recordings to you and you
> could do the same by yourself. It's also hard to say, if there isn't
> more jitter, but 4 ms. At what point starts the attack of a signal
> within the ambient noise level?

Perhaps you could make a stereo recording, the left channel recording the
mic'ed 'tick' of hitting the trigger, the right channel recording the audio
coming from the speakers? You'd say e.g. a loud hi-hat should be recognisable
enough.

> At least I could record FluidSynth DSSI in unison played to the Alesis
> D4 by using different -p values. I'm sure everybody would be able to
> here the problem.

Let's keep this thread restricted to the situation with only ALSA MIDI in
routed directly to ALSA MIDI OUT - it's getting hard to keep track of what's
going on :).


Arnout