Rui Nuno Capela wrote:
> Ralf Mardorf wrote:
>> I'll do a test, 4 to the floor by a soundfont that can be downloaded for
>> free from the internet and than record it and I also will  send the same
>> 4 to the floor to an external drum module. Instead of the Alesis D4 I'll
>> use a Yamaha RX 21 as external Drum sample player next time (I guess the
>> kick isn't at C, so I will transpose the note only for it's MIDI track).
>> I'll TAR the whole Qtractor folder with this test and upload it and hand
>> in the link. I guess I can do it tonight, but I'm not sure.
>>
>> Qtractor, the FluidSynth-DSSI and Audacity will use /mnt/music as path,
>> so you only need to make a link in /mnt to the place were it will be on
>> your machine and change the connections to fit to your hardware.
>>
>> I open recordings by Audacity, to see at what times the events are.
>>
>> To be continued.
>>
>
> may i ask which qtractor version/build will this be running?

spinymouse-s...@64studio:~$ qtractor -v
Qt: 4.4.0
Qtractor: 0.4.1

> fwiw, it might get handy with the latest and current cvs head
> (qtractor-0.4.2.1347+)

There are no JACK headers in the 64 Studio BETA repositories and I won't 
try to set up one of my other, older Linux installations, were JACK1 
running on older kernel versions disconnect clients. I also won't 
compile JACK2 for the 64 Studio BETA, because if something won't be fine 
after doing this, I can't get back the original package, because the 
actual version of JACK2 isn't available any more in the repository ... 
it's a BETA ;), but the first Linux that doesn't disconnect JACK clients :).

> where you can now (finally) select the alsa-seq
> queue timer in effect, besides the usual default/system one. see it in
> view/options.../midi/midi playback/queue timer. there you can opt for
> this newer hrtimer or any of the available pcm slaves instead.
>
> the differences you get with each timer setting would be interesting, if
> any.

I could backup the actual state of my 64 Studio and try to compile JACK2 
and then Qtractor, but to be honest, even then I don't like to do this. 
I could test the different timers with Rosegarden, but at the moment I 
wish to work with Qtractor, so it would be better to do this with 
Qtractor, especially because you program Qtractor and not Rosegarden.

I audacious will ask the 64 studio developers to make 
qtractor-0.4.2.1347+ or the jack header (1.9.2-0.64studio2~hardy1) 
available.

> one other test i'll suggest you to consider, would be sequencing the
> midi track to stand-alone fluidsynth engine (eg. qsynth:) and bounce the
> audio back into a qtractor track. that shall give you some results about
> the internal alsa-seq jitter figures, which should be the ones most
> affected by the timer selection just introduced.

I did it by one of the tests before, fluidsynth-dssi by Qtractor's audio 
outputs to Qtractor audio inputs results in a recording with absolutely 
no jitter but 0.51ms delay, the report is this one: 
http://lists.64studio.com/pipermail/64studio-users/2009-May/003027.html

You don't need to read the linked report, for the test from the link I 
run JACK with -Rdalsa -dhw:0 -r48000 -p64 -n2 and the result was:
"Should be     / left D4 is     / right DSSI is
= 10500.000 ms / ~ 10501.670 ms / ~ 10500.510 ms
= 11000.000 ms / ~ 11001.750 ms / ~ 11000.510 ms
= 11500.000 ms / ~ 11501.775 ms / ~ 11500.510 ms
= 12000.000 ms / ~ 12001.760 ms / ~ 12000.510 ms

The external D4
max. delay + 1.775 ms
min. delay + 1.670 ms

In other words
constant delay + 1.670 ms
jitter         + 0.105 ms

DSSI
constant delay + 0.510 ms
no jitter"

I need to run JACK with -p512 instead of 64 when producing. If there is 
load I can't keep 64 or 128. The maximal jitter for external equipment 
at values higher than 64 will increase. I don't know if there will be 
jitter for the dssi at 512, this will be something I would have tested 
either way and I will do this today.

Wicked :(, the changes for the game port MIDI cable to fit to the 
TERRATEC EWX 24/96 still don't work. TERRATEC seems to ignore the 
specifications for the '2x8 header to d-sub 15pin female and d-sub to 
MIDI IO'. The problem can't be ground ;), this was a typo, but there are 
different pins for +5V in the specifications, but maybe TERRATEC wired 
only one pin. The one who gave me the sound card had the same problem, 
but he can't remember in which way he re-soldered his game port MIDI 
cable. I fear to use a multimeter on an interface, were I don't know 
which pin is an input and which pin an output ;), even if there 
shouldn't be any risk, I believe in Finagle's Law of Dynamic Negatives. 
I sent a new request to TERRATEC and for the expectable worst case 
scenario that they still don't like my provider, I asked a friend at 
another provider to forward my email.

That's why I only can test USB and compare it to the DSSI again, but now 
with the edited rtirq configuration.

Cheers,
Ralf

-- 
http://www.dailywav.com/1002/beginning.wav

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