I have this issue with recording my audio podcasts where i randomly start getting this "clicking" (im not sure clicking is the best way to describe it). It will randomly start after about 10-20 mins and then stop for no apparent reason. Using Audacity on a mid 2012 Macbook Pro with a USB sound card https://www.startech.com/nz/Cards-Adapters/Sound/USB-Audio/Audio-USB-Adapter~ICUSBAUDIOB i tried upgrading the RAM from 4GB to 16GB and still receiving the same issue.

here is an audio sample:

has anyone encountered something similar, what would you recommend?

  • If it's any help, these audio artefacts sometimes appear when streaming and droping connection/loosing packages. Since it's most likely buffer based, ram shouldn't make a difference as you pointed out.
    – Dalv Olan
    Commented Jul 25, 2017 at 10:31

3 Answers 3


It's related to CPU usage priority & streaming the audio into your system from the USB - this has no relation to the RAM & that's why adding RAM didn't help you .

what you are experiencing is called USB Dropouts caused by Interrupts.

finding a good guide to help you optimize your mac for audio recording might actually help you more then adding RAM to your system ...

P.S : you can also try to play around with the Audio to buffer option in the recording preferences


Sounds like you need to increase your audio driver's buffer to prevent packet loss.


It doesn't sound like something in the analog realm or even power supply noise. Sounds like some sort of digital glitching. My first guess is some system resource that Audacity needs is being overtaxed. Probably either CPU or I/O (so I think you were on the right track with the memory upgrade). When I record I typically do the following to ensure maximum system resources...

  1. shutdown "everything" else but Audacity. browsers, mail, productivity apps, etc.
  2. turn off Time Machine (if you use that for back up)
  3. run with electric plugged in
  4. disable energy saving features (or make their kick-in times so long that they don't)
  5. turn off wifi or unplug from the network

I also highly recommend recording to an external drive to eliminate I/O contention. (an Samsung T3 250gb SSD has been working great for me)

If that doesn't help I'd also throw in doing the above AND rebooting prior to launching Audacity to clear things up.

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