Hi, It has been while since I gave you all a good laugh and I am back for more Just a recap for those with short memories SVS PB12 Ultra, hidden away in an alcove. Amp sub level +3db, sub gain 11:00 Connetced via BFD using PEQ to iron out worst of the peaks. Got as far as the first attached gif (alcove.gif) All speakers set to small and crossover set to 60hz I still felt there was a bit of sound missing and the graph seemed to back that up. I just got a new 15m cable from Mark Grant so I could play with different locations. I started with the only real option I have at the moment which is ports about 1 foot from the rear wall (3 feet from the seating position). The nearest side wall is about 2m away so it has a lot more breathing room than tucked away in that alcove with about 10cm all round. I am still running through the BFD but have set it to bypass mode. I decided to run a sweep and the first thing I noticed on the 16hz was a dreadful pneumatic drill/ rapid farting noise. This continues up the next couple of tones to a lesser degree. I am guessing it is running too hot so I dropped the amp sub level to -5db and the amp gain back to 8 oclock. I also changed the crossover to 90hz. The sub is still belting out so much more noise it is amazing. At least 10db even with everything turned back as above. See the sweep on the next attached file (free.gif). I am a bit lost now, the farty noise is still there and quite worrying (although to a lesser degree). Any ideas?