I’m using a Logitech H540 headset to record on Audacity and it takes about 15 seconds to get a normal waveform when recording. The waveform is only tiny bumps until about 15 seconds at which point it becomes a larger, healthy, usable waveform. During the 15 seconds absolutely no adjustments are made. All I do is talk. Any idea of how I could correct this weird fade-in effect? Using Audacity 2.0.3 and Windows 8. I don’t know whether this is helpful or not, but I saw the exact same question in the Mac forum, where the successful advice was to “look in ‘Sound’ in System Preferences. Choose the ‘Input’ tab and if you see it, ensure that ‘Use ambient noise reduction’ is unchecked.”
Ensure that Windows sound enhancements are disabled. See: http://manual.audacityteam.org/o/man/faq_recording_troubleshooting.html#enhancements
If this is a USB headset as it seems, there may not be Windows enhancements for it.
If not, ensure you connect to an empty USB port, not a to a USB hub connected to the USB port. Try changing the cable.
Edit > Preferences… in Audacity, “Recording” section and ensure Audio to buffer is set to 100 milliseconds or a bit less.
I also suggest updating to the current Audacity 2.0.6: http://audacityteam.org/download/windows.
Upgraded to 2.0.6 and the problem disappeared. Thank you!