I finally finished my Adire Shiva/PR sub (EBS alignment) and I am having a problem with the PR. I used Avia and THX optimode disks to do LFE sweeps and around 35hz I believe the PR is resonating and going ballistic all the way out and all the way in and also from 28hz down to 20hz the PR sounds horrible. It makes a flopping noise. When I first built the sub I had a small air leak from one of the screws but I recaulked the screw and everything looks good. ALso just for good measure I put a seal of caulk on the outside of the driver and PR all the way around the outside of it and around the screws. The system is now airtight. I played 35 hours of music (24 hours at low level and 11 at a mid level) and Fight club, Saving Private Ryan, and Gladiator through the sub at medium levels to break it in. I changed the mass of the PR by an additional 100 grams and that did not seem to change anything. Should I build a new cabinet and scrap the PR or could something else be wrong? Ideas? I love the sound of the Shiva! I have a Velo HGS currently and decided the Shiva sounded like fun. I wouldn't say that they are identical by any means however since my Velo was in excess of 1200 and the Shiva was only 400 or so I would say it is a great sub. I am getting ready to build 2 more Shiva's for end tables in my living room. I was going to do the vented EBs alignment for these. Robert Sloan, CCIE "Its not where you go... Its how fast you get there!"