I’m working on narrating my own newly published book. I’m using SSL 2+ as the audio interface with a KMS 105 microphone.
I was using the audiobook mastering macro, and the acx check has been all over the place. But the strangest part of that the nose floor is way too quiet, around -97. RMS is slightly low. I’ve been puzzled by the noise floor being so low as I am recording in the messing around mode and the loud AC is on.
I did a few seconds of recording with no voice, and I got a strange result. The AC is highly audible for exactly one second, and then the background noise totally vanishes. I tried this several times and each time is the same, at exactly one second, all background noise vanishes. I made sure to turn off any windows audio stuff, and made sure zoom wasn’t running in the background.
any clue what I should look for to stop this?
Thank you.
I am about to post a report about Audiobook Mastering Macro behaving badly in Audacity 3.6.0 and 3.6.1. It seems to work OK in 3.5.1 and before. You should probably roll the machine back to 3.5.1 or before until we get this settled.
Get the older Audacity versions from here.
When you get the older one settled, Tools > Reset Configuration.
Koz
Yes. That is the poster child for Hidden Processing. On Windows, remove the internal tools.
https://support.microsoft.com/en-gb/topic/disable-audio-enhancements-0ec686c4-8d79-4588-b7e7-9287dd296f72
Also, close all your Zoom, Skype, Games, Meetings, etc and then do a clean shutdown. Ctl/Alt/Del and then hold Shift while you shut down.
Also, somewhere up in the message thread, roll the machine back to 3.5.1 or before. Don’t forget to Tools > Reset Configuration.
Koz
Great! Thank you.
Richard
Does anyone know of a room tone wav file that can be downloaded anywhere online? My noise floor is 95, so it fails the acx check. Just need to raise it up a little.
Next time, turn of Window Enhancements so it doesn’t apply noise reduction or noise gating when you record…
Of course, save your original before you start adding noise! 
Go to Tracks → New, then Generate ->Noise. into the new track. Choose Pink or Brownian noise.(When you play or export it will be mixed with the original track.) Try a noise amplitude of 0.01 which will be a bit too much… I know it has to be less than -60dB but they don’t tell us what the minimum is. -70dB is probably “perfect”. Use the Amplify effect at around -20dB (or in -10dB steps) until it passes.