On my Auzen X-Fi Prelude 7.1 under Windows Ultimate 64-bit, I noticed that all audio recorded by my microphone (connected via 3.5mm jack into the sound card - I don't have this problem with USB microphones) would play back heavily distorted, as if I were speaking through a spinning fan.
Anyway, I thought I would post a solution that appears to work for me (so far):
1. Right-click on the volume icon in the task bar and select 'Recording Devices'.
2. Ensure that the microphone is set as the Default recording device (indicated by a white tick mark in a green circle).
3. Select the microphone and click on Properties. The microphone properties window pops up.
4. Click on the 'Custom' tab and check the box for 'Microphone +20dB Boost'. This increases the microphone's sensitivity to sound.
5. Click on the 'Levels' tab and move the slide all the way to the right (100) for maximum sensitivity.
6. Click on the 'Advanced' tab. Change the sample rate and bit depth to the following:
"2 channel, 16 bit, 44100 Hz (CD Quality)"
7. Click on 'OK' and then 'OK' again to close down the sound properties window. Audio now picked up by the microphone should now play back free of distortion - test this with a program such as Applian's Freecorder.
While the sample rate setting appears to 'stick', I find that whenever my computer comes out of Sleep mode or reboots, the 'Microphone +20db Boost' check box goes back to being unchecked.
Anyway, if you have been frustrated by distorted audio playback from microphone recordings, I hope this might be of help to you!