Audacity Forum

That's curious - you have three audio clips and they all have different problems.
What did you do different each time?

I altered the input device - generic microphone and microphone array.

Of the three samples here: http://forum.audacityteam.org/viewtopic ... 50#p197150
which one is which?

sorry - I'll have to re-record as I can't remember!

I've managed to improve the recording a bit by reducing the volume of record and playback but the hum is still present. Is it possible that the computer's fan is creating it?

Clips 1 and 3 (microphone generic) has repeated short bursts of noise creating a "motorboat" effect. This is probably because some part of the computer cannot keep up with the amount of audio data.

Clips 2 and 4 have worked "perfectly" - the "only" problem there is that the sound quality of the built in mic array is rubbish (usually the case on laptop and notepad computers).

There probably isn't anything that you can do about the sound quality of the built in mic array apart from turn down the recording volume and speak closer to the built in microphones.

For the USB headset, I think the sound quality will be much better if only we can stop that motorboat effect.
Go into "Preferences" (Effect menu) and in the "Recording" section, try increasing the "Audio buffer" setting. The default is 100 milliseconds. Try increasing it to 150. If necessary keep increasing it in 50 millisecond steps up to a maximum of about 300 milliseconds.

If you find that a higher setting fixes the problem with the USB mic, you will need to then set up the "Latency Correction" so that when you "overdub" new tracks over existing tracks, the tracks are kept synchronised. See here for how to do the latency correction: http://manual.audacityteam.org/o/man/latency_test.html