Audio fades after 3 seconds while recording again.

I had kept on version 2.0.5 for years because of this audio fading out issue. 2.0.5 was the last version I found that it would record the full length of a tone for me without fading out. Unfortunately due to some unplanned computer upgrades to macOS Catalina 10.15.7 Audacity version 2.0.5 is no longer supported for me to use so I had to update to version 2.4.2 and this is happening again. If I try to record any tones over 2 or 3 seconds in length it fades to basically nothing so this is still happening on newer versions. This is EXTREMELY frustrating when trying to record tones that are 8 to 10 seconds long and having it fade after about 3 seconds each time.
My computer settings have been checked and are seeming to be fine unless there is some hidden setting I’m missing. My built in mic settings have no noise reduction or filter settings the manual and help sections recommend trying that may cause the drop off. And I can’t find any way to fix this in any of the Audacity settings. So I have no idea why the older versions up to 2.0.5 worked fine to record longer than 3 seconds without fading out but the newer versions basically make my using this for recording almost useless.

If it works I added a screen cap of a recording I just threw together quickly as an example. You’ll see it records fine for the first 3 or 4 seconds then the level drops off (I DID use the Amplify effect after recording so it can be seen easier but did no other edits). Everything in the whole recording of that tone should look and sound as it does in the first 3 or so seconds of it’s recording. The tone length should be 8 to 10 seconds in duration and a steady 716Hz if anyone can try and replicate or find a solution.
Screen Shot 2020-10-02 at 3.53.11 AM.jpg

That’s the signature distortion of Automatic Noise Reduction. Any sound that’s constant for a set amount of time must be “background noise” and get rid of it. Auto Noise Reduction can work OK for speech, but hates music for obvious reasons.

Audacity doesn’t apply filters, effects, or corrections during recording, so it’s down to what the computer is doing.

Apple (upper left) > System Preferences > Sound > Input. The Mac internal microphone has a selector for [_] Use Ambient Noise Reduction.

But that’s far from the only place the effect can pop up. Zoom, Skype, iChat, any communications or conference program is likely to have this effect and worse, may remain working after the app is closed. So if you have Zoom hanging around waiting for an incoming call, that’s the kiss of death right there. These apps are not shy or bashful. They work and are successful because of their ability to run no matter what, so they grab your sound services with an iron fist and work their will.

Look at your dock (usually) at the bottom of your screen and see which applications are working by the check or light under each app. Anything suspicious or that you can’t identify?

Amazon Live Chat?


It’s not a mystery why they do this, either. If you have a 3 by 4 checkerboard of people in your Zoom, what would happen if they all had air conditioning or computer fan noise in the conference?


Catalina doesn’t have the ambient noise reduction in the sound settings.

Earlier versions of Audacity handled these types of recordings flawlessly. Only the newer versions drop the sound. I’ve dealt with this issue before when I updated Audacity in the past on various macOS and always had to revert back to the 2.0.5 version of Audacity to be able to get it working again. But now unfortunately being on Catalina going back to 2.0.5 again is not an option.

But now unfortunately being on Catalina going back to 2.0.5 again is not an option.

No, but reversing the Catalina update is.

The update to Catalina was not universally popular. If it stopped your workflow, then it’s not popular with you, either.


Catalina doesn’t have the ambient noise reduction in the sound settings.

Does your machine have a built-in microphone? That where it appears on mine.