I recently got a portable DVD player for Christmas (CyberHome) and so far, have loved using it. However, I've noticed that for whatever reason, when I play a double-sided disc, the audio is almost non-existent. This is only with these types of DVDs. All others have great audio, but I can barely hear the audio at the maximum volume with the double-sided discs. Is this a defect and I should look into getting it replaced or is there another explanation? Thanks.