Sudden volume drop

I record vocal learning tracks, using a Yeti Blue microphone and Audacity. With either my Yeti Blue, or my Logitech webcam (both of which connect thru USB ports), a constant pitch sound maintains volume for about 1 sec and then falls off dramatically, as recorded on Audacity. If the frequency changes it returns to proper volume but only for another second.
Attached is a recording of two experiments, the first, a constant pitch, the second, starting with one pitch, running thru several pitches and then stopping on a pitch.
Is this a computer problem or an Audacity problem? (I uninstalled Audacity and reinstalled it, the 2.3.0 version)

Here is the data on my computer:
CPU: Intel Core i3-7100
GPU: Intel HD 630
HDD: Toshiba DT01ACA100 1TB
MBD: Dell Inspiron 3668

That’s textbook Environment or Voice Processing.

Oh, I guess step one is Audacity doesn’t apply anything during recording.

One major difference between background noise, hum or other sound and your voice is the duration. If you have one sound there for an extended time, it must be noise therefore we shall memorize it and subtract it from the show. This works a treat when you’re having a business conference call to the home office in Geneva from a noisy office, but a good deal less well when you’re trying to sing. The filters tend not to pass music at all.


One more. Skype, Chat and other communications services can have their own processing and add them to whatever Windows is doing. Make sure you stop dead and close all your chat apps before you record anything critical.


Thanks for the quick response.
Two things:

  1. Using the direct mic test in windows, the effect is immediately apparent. I’ll attach a snapshot of a constant volume at the beginning, but within a second, it has dropped to a quarter of the blue line.
  2. I have tried my hardest to find anything about enhancements in the sound control panel, and no results.
    Mic test in Windows.jpg

Did the webcam come with drivers?

Are you shocked that one of the recommendations for reading high quality audiobook material is stop using the computer…

I have no idea how to check for that stuff in Windows. A Windows forum elf will be along. Or Google.

Have you fresh started your machine? In WIN10: Shift-Shutdown, Wait and then Start. That’s a deeper clear-start than the normal shutdowns.


Nobody would be surprised if the webcam had processing built-in, but I’m pretty sure the Yeti doesn’t. Do both microphones do this?


Well, by golly, you are right. Problem solved. Yeti works, webcam doesnt.

I’m not entirely sure which of the following steps were necessary/sufficient, so I’ll list them all, for others’ benefit.

Uninstalled/reinstalled Audacity (2.3.0)
Fresh started computer, per your suggestion: In WIN10: Shift-Shutdown, Wait and then Start.
Found “enhancements” on the playback page, not the recording page, (where I had looked for it before.) Therefore I was able to:
Sound > playback > Speakers USB Audio Device > Properties > Enhancements > Disable

Thanks again.

Hey John, glad you got it resolved.