Moving the mic slider from max to zero does not reduce the input volume for my USB condenser mic or my headphone mic. I am using version 3.1.3 now. It used to work perfectly on version 2.4.2 with the same computer and same microphone. (The only way I can reduce clipping is to move the mic far away across the room from my voice or guitar using a 15’ USB extension.)
If I close Audacity, i can reduce the mic input volume in windows settings - but I cannot adjust the mic input volume in windows settings while Audacity is running because the App takes control of the mic.
That’s not unusual with USB devices but I don’t know why sometimes it works. Except sometimes the USB device has volume control built into its hardware & driver or sometimes there is special software to control it. Most USB audio interfaces and some “podcast mics” have a physical volume control knob.
The only way I can reduce clipping is to move the mic far away across the room
It’s the analog-to-digital converter built into the mic that clips so you have to reduce the analog level before it goes to the DAC.
And, note that Audacity “shows red” for potential clipping. If you have clipping and you reduce the level, Audacity won’t show red but the wave is still clipped. Or, if you boost the level in Audacity and the peaks go over 0dB it will show red even though the wave isn’t clipped until you play or export.
But it is unusual for a USB mic (that doesn’t have a recording level knob) to clip “easily”. Usually they are intentionally designed with low-sensitivity.