I have no idea on the sample rate. I'm using THX sound that is 15 seconds in length and it is over in about 3 seconds. I've tried other wav files from my laptop as well. Some do not play at all and others that are just beeps and bongs about 1 second long seem fine. It won't play anything with a human voice in it no matter what the length. As far as the macros, I've created new ones with the same results. A 4 second macro is executed in close to 2 seconds. Even the IR code seems to be sent more quickly as evidenced by the flash rate on my IR recievers status LED. The Satellite reciever still responds correctly to channel macros but my DVD changer has a little trouble keeping up