I have recently bought a 3rd gen airport express so that I can use airplay with hi-fis in two different rooms. I've had my 2nd gen for many years and never had a problem with it. But when i listen to music from the 3rd gen, it keeps lagging (once or twice in a 5min song). It's not awful, but its annoying and not what I would expect from an apple product. So far I have tried swapping the airports over, using in different rooms, and replacing the new airport but it keeps happening only with the newer airport. Is there a reason for this? Or could it be my 3rd party wi-fi router (BT Home Hub 4.0). Many thanks for any thoughts!!