When I record a terrestrial tv station (through aerial) to HDD in SP mode, on playback the sound drops off for about a second. This happens maybe 2 or 3 times per hour of recording. There's no loss in picture just an annoying stutter every now and again. I've re-formatted the HDD, had my aerial, leads, etc checked and am running power through a zapcatcher with an emi filter. Marginal reception has been suggested but the TV tech reckoned reception was fine. There's no sound problems when playing commercial DVDs. Help ...!