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

[Ralf Mardorf]

On Thu, 2010-07-15 at 00:46 +0200, fons at kokkinizita.net wrote:
> On Wed, Jul 14, 2010 at 11:54:35PM +0200, Ralf Mardorf wrote:
> 
> > 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.
> 
> That is not a valid test. If the soft instrument that generates
> these sounds aligns MIDI events to Jack periods, and you are using
> a period size of 1024 as you say you are, it proves nothing at all.
> 
> Apart from that, it remains to be seen if *real* timing errors of
> +/- 2 ms do 'destroy the groove'. To test this, make the same 
> recording 
> 
> - without jitter,
> - with 1 ms jitter,
> - with 2 ms jitter,
> - with 3 ms jitter.
> 
> and check if listeners are able to identify which is which,
> or at least to put them into order.

I know very gifted musicians who do like me and they always 'preach'
that I should stop using modern computers and I don't know much averaged
people. So the listeners in my flat for sure would be able to hear even
failure that I'm unable to hear.

> What you have been doing so far is compare an 'exact' version
> with one that has some unkown and uncontrolled errors. You could
> 'prove' anything you want in that way.
> 
> You are just jumping to conclusions and making gratituous
> generalisations.
> 
> 
> Ciao,

No doubt about it, I'm speculating.

Earlier I send somebody an email off-list (see below), anyway, even when
playing live by using ALSA MIDI just thru, there is latency, with or
without jitter, but off course without negative delay ;).

My speculations might be wrong. But there are audible issues and I'm
sure that even non-musicians are able to hear it, unfortunately I'm some
kind of freak, all the people I could ask to listen to this issues are
highly gifted musicians, unfortunately the averaged German soccer, radio
prime time, heavy rotation, music listening audience is beyond the
people that I know.

Anyway. this crowd shouldn't be the benchmark for good music. Am I
wrong?

I don't no what's bad, but something is absolutely bad for hw MIDI.

-------- Forwarded Message --------
From: Ralf Mardorf
To: [snip]
Subject: [off-list]
Date: Thu, 15 Jul 2010 00:22:17 +0200

ASAP, I guess later today (here it's 00:15 o'clock), I'll run jackd,
resp. the alsa driver with 4096frames/period at 44.1KHz and record the
external synth to the left and the virtual synth to the right channel.
This should give a clear result, regarding to the 'event happened,
before it was triggert' issue. I guess even for quantum physics such
phenomena are caused because of technical issues.

:D


Cheers!
Ralf