THD is the total harmonic disortion. For most 'untrained' ears, anything below 1% is not really audible. Trained ears, in combination with accurate components, will hear even lower THD values...

10% THD is definately audible, and it's really that bad. With good equipment, it would probably sound awful.

chances are that with your PC speakers, you won't really notice much of the THD, since the speakers themselves are so inaccurate that it will sound 'disorted' all the time...

Keep them spinning,
Bert.