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Getting input/output jitter from time to time reported by JK

Hi there,

I am new to JamKazam. I recently bought a UMC202HD Behringer Audio interface. Have not had the chance to use it a lot on JamKazam, but when I have used it the audio quality has been great. Currently using 48KHz for sampling with 2.5ms for frame size. My system is a 2008 iMAC with 6GB RAM and OS X 10.10.5.

I got green boxes most of the time when I was doing the initial setup. Sometimes got yellow variance (fair I think it was) results.

So my questions:

- I wanted to know how abnormal is to get yellow indicators on the input and output jitter. I do get them from time to time both, using the Behringer audio interface and just the default imac Mic headphone on the computer. The actual latency I get from the UMC2020HD audio interface is 9.3ms, while the latency I get when using the default Mac mic and midi tracks is 7ms. I tested midi with an M-audio keyboard.

- I am wondering how involved is the actual computer when getting that input/ouput jitter. My mac is very old, like I said 2008 iMac. Based on what I have read in the forum the jitter is actually from the audio interface, but the fact is that get similar results with and without the external audio interface.

- I have noticed that frame size can be used at 2ms or lower, although they say experimental, what is the recommended frame size? Not sure if you can explain the actual meaning of the frame size.

- What is the recommended freq, 44.1KHz or 48KHz, I have seen some postings indicating to try different combinations of sampling and frame size. It all depends on the audio interface or that will depend on the computers, but wanted to understand if there is a reason to use one or the other.

Thanks a lot for the answers.



  • Hi Juan
    The experimental frame sizes dont currently work. Always use 48 k for best performance since 44.1 would be up sampled to 48 k. Dont worry about the yellow status indicator. If its turning red and stays red then you likely have network issues but the status yellow/green is fairly normal on most home networks. Now all that being said and please all those reading this, old computers will likely not cut it here for live sessions. In some cases you can do a 1 to 1 session but if you want to use the new features like fixed rate bit streaming and multiple players plus video and your tube live or internal media playback its time to get a decent CPU (I3 or higher) and thats not a computer built in 2008. For a simple one on one lesson you can use an older computer but when its critical that you have the lowest latency, do yourself a favor and get a newer CPU and a low latency audio device.
  • Hi Mark

    Thanks for the quick reply and clarification to my questions.

    Getting such a good quality on the tests I did, with such an old computer tells me that the app and my gear are getting along. Agreed, a newer and better computer is a must and my next step.

    As far as the fixed rate bit streaming options you make reference to, is there any documentation on that to understand when to change those parameters? Looking at my app I presume this is configured in the Manage > Audio Settings > Audio Boost / Packet Rate Configuration menus, correct? I noticed my options for Bitrate and Network Packet Rate by default are checked in Auto Throttle.

  • With your computer best bet is leave the auto throttle enabled
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