New OS+New Audacity =glitching HELP

Thanks for any and all help and advice. I am definitely not an engineer or incredibly tech savvy so I pretty much need my hand held when trying to understand some of this stuff (like open this, go here, then click that). I have used Audacity on a Mac for many years for recording straight voiceover. No major issues. Until the other day when I had to install High Sierra due to other applications having problems (I had still been running Yosemite). I also installed the latest version of Audacity 2.1.1 Now when I record I either A) have small dropouts along the way–glitches if you will–parts of words missing which I hear in the exact same spot every time I play the file. Or B) It sounds O.K., but upon further review I will begin to hear glitching…which wasn’t there the first time I listened. In the first instance it’s absolutely glitching during recording. But in the second…why would I hear it sometimes and other times not? And how to I fix either problem? I’ve tried googling this and done everything I can figure out how to do. Thanks very much

Please try the suggestions on this page in the manual.
– Bill

I will do that. I have tried multiple suggestions I’ve found in this forum and others already. Also it is audacity 2.2.1-- I mistyped it in the original post. Thank you.

As it turns out, I had previously visited that page and already done all of that. Everything seems to be set correctly. Another engineer told me to do just the opposite with the buffering…to set it as high as I possibly could. That didn’t do anything either :frowning: Any other ideas? Again, it just started with the new OS and the New Audacity and sometimes glitches on recording, and sometimes in various spots when playing back.

Sorry, I can’t offer any other advice. This problem has been vexing the developers, since no-one has been able to set up a situation where this happens reliably while debugging.

Yes, setting the buffer length shorter seems counter-intuitive, but it is our experience that it usually helps.

– Bill

This is specific to Mac, and is the most common cause of glitching on modern Macs. On other platforms (Windows / Linux), the usual approach would be to increase the buffer length, but Apple did something a few years ago to the Mac sound system and we suddenly found that a lot of Mac users started getting clicks in their recordings. After some experimentation, we found that Audacity’s default 100 ms buffer size was implicated (although that has been the default for over a decade). The solution to this specific problem was to decrease Audacity’s buffer size. As far as I’m aware, Apple has never released information about the change that caused this, but if anyone knows otherwise, we would love to hear.

While less common on Mac computers, there’s a host of other things that can cause audio glitches. This page in the manual covers many of them: FAQ:Recording - Troubleshooting - Audacity Manual and more on the wiki: Missing features - Audacity Support . Although that article is written mostly from a Windows perspective, many of the issues can also apply to Mac and Linux

Though I am not using High Sierra at present I have used it and found three things that helped on my MacBook Pro. You have probably tried the first two, but wanted to list them anyway.

  1. Reduced the buffer length to 20ms.
  2. Turn off App Nap - only applicable if using a laptop.
  3. Turn off the display sleep or make it a long time before sleeping so it doesn’t happen during recording.