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Jack sample rate difference. Jamulus won't start

Gilgongo
2020-12-24
2020-12-25
  • Gilgongo

    Gilgongo - 2020-12-24

    I'm using Jamulus with a new audio interface which works at 48000 OK as far as I can tell. However, when I try to use it with Jack on Ubuntu, Jamulus says it's not running at the right sample rate. Jack, however, seems to say it is in the startup log, but then it says it isn't in the status tab (see image).

    Also, I notice that under Windows, if I try to switch to the new interface in the Jamulus setting, it says it can't be initialised.

    Does anyone know what's going on?

     
  • DonC

    DonC - 2020-12-24

    Does it say somewhere in that log that the configuration was successful at 48k?
    I would read what I can see there as, it tried to configure at 48k, but was not successful.

     
    • Gilgongo

      Gilgongo - 2020-12-24

      Doesn't seem to so show any errors in the log. I dunno, maybe it's not compatible.

      Thu Dec 24 22:18:16 2020: JACK server starting in realtime mode with priority 10
      Thu Dec 24 22:18:16 2020: self-connect-mode is "Don't restrict self connect requests"
      Thu Dec 24 22:18:16 2020: Acquired audio card Audio0
      Thu Dec 24 22:18:16 2020: creating alsa driver ... hw:TD27|hw:TD27|128|2|48000|0|0|nomon|swmeter|-|32bit
      Thu Dec 24 22:18:16 2020: configuring for 48000Hz, period = 128 frames (2.7 ms), buffer = 2 periods
      Thu Dec 24 22:18:16 2020: ALSA: final selected sample format for capture: 32bit float little-endian
      Thu Dec 24 22:18:16 2020: ALSA: use 2 periods for capture
      Thu Dec 24 22:18:16 2020: ALSA: final selected sample format for playback: 32bit float little-endian
      Thu Dec 24 22:18:16 2020: ALSA: use 2 periods for playback
      Thu Dec 24 22:18:16 2020: graph reorder: new port 'system:capture_1'
      Thu Dec 24 22:18:16 2020: New client 'system' with PID 0
      
       
  • Ignotus

    Ignotus - 2020-12-25

    I just looked up the manual for the TD27 and it says the "original" sample rate is 44.1 kHz but that with a sampling converter it can do 48 and 96 kHz. No idea what that means though - maybe there's a setting in the module to change that. It looks like Jack itself can't change the sampling rate.

    I'd ask on the vdrums forum - loads of experienced Roland kit owners there.

     
    • Gilgongo

      Gilgongo - 2020-12-25

      OK thanks - the ASIO driver (that gets downloaded by Windows when you connect the TD27) lets you change it from 44.1 to 48, so there's hope maybe. I'll ask on the forum what the reference to "sampling converter" might mean.

      I wonder if maybe in 50 or 100 years time this stuff will be easier?

       
  • Ignotus

    Ignotus - 2020-12-25

    It's quite possible that without the Roland driver you can't change the sample rate, and I doubt Roland supports Linux.

     
    • Gilgongo

      Gilgongo - 2020-12-25

      Yes, that seems likely. The fact that I can't switch to the device under windows is also a bit annoying too.

      EDIT: Actually, I've got Windows working now (down to 128ms), but now think that the TD27 can't be set up to listen to the incoming signal so it may not be possible to us it anyway. Hm.

       

      Last edit: Gilgongo 2020-12-25
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