Hi :)

while 64 Studio 3.0-beta3 don't have time-outs and Jack never disconnect 
clients and I started playing around with MIDI, I was fine. Then someone 
from the community asked me to do vocals, so I tried to make a demo and 
the demo failed. A non-musician woman was fine with the demo, but for 
musicians it's disgusting.

Were should I post this? I'll start with the 64 Studio lists. Please 
note that I'm subscribed to both lists, but I only receive mail from the 
user list, not from the developers list.

Is it the 64 Studio kernel? Is it Qtractor (I don't think so)? Is it Jack?

Qtractor MIDI out by an USB MIDI device (swissonic) --> MIDI in external 
19" drum sample module (Alesis D4, dry kick with sharp attack)

$ jackd -Rdalsa -dhw:0 -r48000 -p256 -n2
= Latency 10.7 ms

WAV Microsoft Signed 24-Bit

I looked at the recording done with Qtractor by Audacity. It's 4 to the 
floor, with one beat 'pre-recorded' at 120 BPM.

Should be    / is
=  500.000 ms/ ~  502.400 ms
= 1000.000 ms/ ~ 1002.450 ms
= 1500.000 ms/ ~ 1502.425 ms
= 2000.000 ms/ ~ 2001.400 ms
= 2500.000 ms/ ~ 2501.450 ms
= 3000.000 ms/ ~ 3001.500 ms
= 3500.000 ms/ ~ 3501.725 ms
= 4000.000 ms/ ~ 4001.500 ms

max. delay + 2.45 ms ~ 1/2 Buffer
min. delay + 1.40 ms ~ 1/4 Buffer
no negative delay

In other words
constant delay + 1.40 ms ~ 1/4 Buffer
and max jitter + 1.05 ms ~ 1/5 Buffer

The effect is well known, playing the MIDI kick and recorded kick in 
unison, it sounds like an early reflection.

I made a vocal demos and a femal bassist said, that I was to late in 
timing on the recording, while I didn't notice that my self, doing it in 
a hurry. The next day I tried to make a more serious vocal demo and I 
tried to do syncopated phrasing. After some takes I tried to compensate 
the computer technical trouble by my phrasing and did a disgusting 
phrasing because of this.

Not everyone can hear this. I don't know any non-musician who is able to 
hear this (excepted to the early reflection like effect), but I also 
don't know any musicians who do not hear this.

Any thing I can do to fix it? I've got one idea myself, it should be 
possible to reduce the latency by decreasing the Frames, what will cause 
less time/buffer. With my rt-audio unstable Linux distros I did this and 
only had jitter for a real phasing (= flanging like sound instead of an 
early reflection like one) when I played a MIDI and recorded kick in unison.

Cheers,
Ralf
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