Poor quality is possibly noise from your other hardware in your PC. Your CD-ROM has a cable running from it directly to your sound card and thus makes music played from it clearer. At your place of work do you have access to a CD writer; if you do it would be an ideal way to test if it is the mp3 or just radio frequency interference. When you plug in an effect to your instrument and there is an air or humming noise this is kind of the same thing ten cycle hum or R.F.I. This is just a guess. Blake