i got a new sub today, and have been playing with it all day. i used a tone generator and made pure sine waves at 20hz, 19hz, 18hz, 17hz, and 16hz, and then burnt it onto a cd from the .wav file. i put it in my dvd player (its also the cd player at the moment) and played the first track (20Hz). to my suprise there was a signifigant amount of noise from all five speakers plus the sub. obviously, the stuff coming out of the bookshelf speakers was just distortion, but it confused and disturbed me. my reciver is an onkyo 575x, the speakers are jbl n24s, n26s, and ncenter. i checked immediately after to make sure the speakers were set up and they were (subwoofer on, all speakers set to small). i dont know for sure what the onkyo crossover is, but i think its 80hz. does anyone have any idea why this is happening?