Just bought the Philips SBC HC8850. I realise that these are the cheaper end of the market and you usually get what you pay for. However, is it the norm for cordless headphones to have quite a bit of interference. I understand that they are transmitting a FM signal but what's the point of making cordless headphones you get a hissing background noise from them. I've tried retuning numerous times but doesn't make any difference. Can anyone recommend a pair that under £100 that doesn't have too much interference. I want them for listening to DVDs and music. The Philips have a pseudo surround sound so would be looking for something comparable.