And it sounds like its coming from the port. I didn't get my pro-amp hooked up(technical glich ) But me not being able to wait to hear it and to check for leaks I hooked it up to my 300watt amp. I played a 20hz sinewave and turned up the volume. I got this horrible noise. It sounded like a leak so I took the driver out(not easy) and sealed it good and reinstalled it. The second time I still have the noise but listening closer it sounds like it is coming from the port. The sub is in a 160l enclosure with a 6" port, 28" long not including the 6" port flares. I can't believe it is coming fron the port with only 300watts and my sub has a 1/4" bead of silicone underneath and around the perimeter. Is this right can I have audible noise from the port at such low volumes? Also, I didn't use PVC or sewerpipe but sonotube for the port. It doesn't fit tight as it should but I've got it pretty good. It has a slight edge could that be it. And lastly If it were a leak would I hear it at all all frequencies? I only hear the noise at 20-26hz. Any help?