Can you record the noise from BW-generator so you can put a preset onto your mp3 and listen to it with earphones when your in bed ?

I thought about recording it whilst playing using windows sound recorder, but it wouldnot be completely accurate as my speakers are different distances from computer and produce some distortion.

Is there anyway to get a preset noise into a mp3 compatible form without quality loss ?

Oh I thought this would be a noobish question therefore i posted here.