[Jack-Devel] synchronization with Jack transport

classic Classic list List threaded Threaded
4 messages Options
Reply | Threaded
Open this post in threaded view
|

[Jack-Devel] synchronization with Jack transport

Philippe GARCIA-ORTUNO

Hello,

I have a problem of synchronization with Jack: for a song at a tempo of 120bpm I drive several synths including a hardware Tempest in  slave mode with seq24 disconnected from jack transport and everything is fine. But if I connect seq24 to Jack my Tempest suddenly turns much more slowly, I would say almost half the tempo.
Would you have any idea where the problem might come from?

thank you in advance for your help, best regards,

Philippe

_______________________________________________
Jack-Devel mailing list
[hidden email]
http://lists.jackaudio.org/listinfo.cgi/jack-devel-jackaudio.org
Reply | Threaded
Open this post in threaded view
|

Re: synchronization with Jack transport

Christopher Arndt
Am 03.10.19 um 01:04 schrieb Philippe GARCIA-ORTUNO:
> But if I connect seq24 to Jack my Tempest suddenly turns much more
> slowly, I would say almost half the tempo.

Sounds like seq24 is sending MIDI clock messages to your MIDI output,
where the Tempest is connected too. You should be able to change this in
the options window of seq24.

It is also maybe acting as the JACK "timebase master", i.e. setting the
tempo information for JACK transport clients. I'm not sure, though,
whether seq24 does this. If not, some other JACK client must be doing
this, and seq24 is adapting its internal tempo to it, as soon as it is
set to follow JACK transport. What other JACK programs do you have running?

You can use the jack_transport console tool to act as a timebase master
(overrides any existing timebase master) and set the tempo:

$ jack_transport
 > tempo 100
 > master
 > play

AFAICS, jack_transport does not support setting the meter (beats-per-bar
and beat-length) to something other than 4/4, For that you'd need
another program, e.g. Carla, Ardour, etc. I also wrote a simple Python
script (based on the jackclient-python library), which supports
providing the tempo and meter.

https://github.com/SpotlightKid/jack-audio-tools/blob/master/transport/timebase_master.py 


The script is not a real-time safe solution, but is nice for testing.


Chris
_______________________________________________
Jack-Devel mailing list
[hidden email]
http://lists.jackaudio.org/listinfo.cgi/jack-devel-jackaudio.org
Reply | Threaded
Open this post in threaded view
|

Re: synchronization with Jack transport

Christopher Arndt
(Re-directing the discussion to the mailing list again.)

Am 03.10.19 um 15:03 schrieb Philippe GARCIA-ORTUNO:
> Yesterday I made a test to connect seq24 (in seq24 send the clock to
> midi Throught and then connect midi Trought to Ardour MMC,
> Ardour+seq24+Tempest played well at 120).

So is Ardour normally involved in your setup? Can you describe exactly,
which (audio) software you are running and what is connected where and
to what (audio and midi, ALSA, JACK and hardware MIDI connections)? Try
to create a minimal setup, which still exhibits the problem.



Chris
_______________________________________________
Jack-Devel mailing list
[hidden email]
http://lists.jackaudio.org/listinfo.cgi/jack-devel-jackaudio.org
Reply | Threaded
Open this post in threaded view
|

Re: synchronization with Jack transport

Philippe GARCIA-ORTUNO
Yes I often use Ardour and Mixbus32c  but I do not actually use it for this problem: I just use seq24, seq64 and Giada:

I am on ubuntu studio64 with 2 multiface II sound cards + ESI M4U Xt midi usb interface

Try to create a minimal setup, which still exhibits the problem:

With seq24 I control 4 synthesizers : SE-02, Andromeda, Solaris and a Q Rack with midi pattern + the DSI Tempest set as slave and all are connected in seq24 interface. The seq24 different patterns are connected to the different synthesizers by this way: just right click in the pattern and choose the midi bus. In the option menu of seq24 I put on the midi clock on the midi channel of the tempest :  [4] 28:3 (ESI M4U XT midi 4) ---> on 

At this time everybody work fine but when I wanted to record the pattern loops in Giada (audio software) I had to connect Giada and seq24 to jack to make them synchronize and at this time I had the problem with the Tempest: 77 bpm  instead of 120 bpm. At the beginning I thought that it was the fault of Giada but when I eliminated Giada of the setup, the problem persisted. It appears when I connect seq24 to jack.

So
to summarize the moment when the problem appears, I do not use audio software, only midi with seq24 which drives the synthesizers and the Tempest as Slave.

To have a minimal setup now which still exhibits the problem, now I have only seq24 connected to the Tempest.

(I also tried  to connect the Tempest to my master midi i/o multiface but the problem persist.)

Philippe


Le 03/10/2019 à 17:10, Christopher Arndt a écrit :
(Re-directing the discussion to the mailing list again.)

Am 03.10.19 um 15:03 schrieb Philippe GARCIA-ORTUNO:
Yesterday I made a test to connect seq24 (in seq24 send the clock to midi Throught and then connect midi Trought to Ardour MMC, Ardour+seq24+Tempest played well at 120).

So is Ardour normally involved in your setup? Can you describe exactly, which (audio) software you are running and what is connected where and to what (audio and midi, ALSA, JACK and hardware MIDI connections)? Try to create a minimal setup, which still exhibits the problem.



Chris
_______________________________________________
Jack-Devel mailing list
[hidden email]
http://lists.jackaudio.org/listinfo.cgi/jack-devel-jackaudio.org



_______________________________________________
Jack-Devel mailing list
[hidden email]
http://lists.jackaudio.org/listinfo.cgi/jack-devel-jackaudio.org