Suddenly Everything Went Distorted

I’ve been using Audacity (2.3.2) for years, doing LP cleanup. In the middle of a project yesterday, the output quite suddenly became overdriven and distorted. Waveforms look normal but the output is unlistenable.

I can turn the output volume down, on either my iMac (10.15.7) or in Audacity, but if they’re up enough to be audible at all, they’re 100% distorted.

At first I thought my powered computer speakers had crapped out, but removing them and plugging my headphones directly into the Mac gives the same distortion. I cold booted my computer, and downloded & installed the latest Audacity (2.4.2) = same problem.

And it’s only Audacity. Apple Music works normally.

I’m baffled.

[Later:] Okay, this gets weirder. I just opened the next file on the album, and it’s fine. The distortion seems to be confined to the LAST file I worked on. Again, the waveforms onscreen are totally normal, but any kind of playback is impossible due to wide-open volume. I guess the next thing to try is to save the file as-it-is, in another file format besides .AUD, and see if I can edit it as an .AIFF?

Just a longshot…

Have you tried opening Audio/Midi setup (in /Applications/Utilities) and checking and reaffirming settings there?

In rare occasions, this fixes Core audio if it seems “stuck” like this.

Uh, yeah. The AIFF is totally messed up.
Screen Shot 2020-10-30 at 4.52.53 AM.png
For comparison, here’s what it looks like in Audacity:
Screen Shot 2020-10-30 at 4.56.45 AM.png

Problem solved.

See that volume control in the upper left corner? It’s not supposed to be all the way to the right. I must’ve bumped it. Took it back to 0dB and now everything’s fine. Whew.

Good to know it’s solved!

Yeah, once again I heard hoofbeats and looked for zebras.