Since completing my diy tempest, I've been putting it through the paces. As I do not have the rest of my HT setup I've been testing it mostly with music. I recently played the first song on the album "Songs for the deaf" off the Queens of the Stone Age album. It's not quite a song but more of an intro... but my god does it have insanely deep bass. I am positive that it is playing down to nearly 15hz with power. This test showed a fairly annoying flaw in my design. I have 2 4" ports tuned to ~18hz, with flares on the outer end. But when the sub get's waaay down I get a lot of port noise. I first thought it was the tinsel slapping, but I'm quite sure it is the air in the tube. I then tried a tone generator, and once again it does seem to chuff at ~22hz and down, even at fairly moderate volumes. I was thinking that putting a high pass filter set at 20hz would help. Is there any way to stop or fix this without increasing the port diameter? I built the port flares by hand so increasing the diameter would be a MAJOR pain. The flare radius is quite large, and was not done with a router. For 99% of music the sub will still perform quite well, but HT is my main concern. I threw Matrix: revolutions in and went to the conversation with the deus ex machina. At a comfortable listening level (sorry no spl meter yet... will get one soon) there was some noticable chuff but it wasn't too bad. Please help!