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Jamulus Sample Rate Suggestion

2020-06-23
2020-06-24
  • Anthony Holland

    Anthony Holland - 2020-06-23

    Hello Jamulus Gurus,

    I have a suggestion for Jamulus….

    It seems to me that you might want to have an option for the user to Lower the sample rate for Jamulus. Right now, I think it works at 48kHz, but I think if you ran a 22.05kHz sample rate that would reduce the data load greatly and still be acceptable in sound quality. That would give you a Nyquist (max) frequency of 11kHz, which for folks needing real time online jamming/rehearsing would be good enough.

    I’ve done lots of hearing tests with my college students and found that many can’t hear past 17kHz, some not past 14 kHz and of course anybody over about age 40 probably can’t hear much above 11kHz anyhow….(as we age we loose our upper frequency range )…. And by allowing the user to select 22kHz as a sample rate, you lower the amount of data you need to get across the internet in real time.

    Would be a great feature! Select your sample rate! 22.05kHz sample rate!

    Thanks for Jamulus dear Gurus!

    A. Holland
    Skidmore College

     
  • Luuk

    Luuk - 2020-06-23

    I think topic starter confuses sample frequencies (rates) with audio frequencies.
    With a sample frequency (rate) of 22.05kHz you will be able to reproduce everything from 0 Hz (20 Hz) to 10 000 Hz, with a sample frequency of 44.1 it will be 20 kHz, I'm sure a lot of people will notice that difference.

     
  • DonC

    DonC - 2020-06-23

    The starter's comments are correct, citing Nyquist etc. But Jamulus is sending compressed data, not straight samples. I do not know the specifics of how the OPUS codec compresses, but I would think that limiting the frequency bandpass would be one of the obvious methods used during compression. And from listening to the differences between high and low quality I think that one hears that too, along with a big reduction in the dynamic range.
    Best, Don

     
    • Luuk

      Luuk - 2020-06-23

      "The starter's comments are correct".
      I am not convinced.

       

      Last edit: Luuk 2020-06-23