Took me the best part of 6 hours though. The BFD was the dogs danglies. Now I have a nice graph starting around 18Hz @ 87db right down to 80Hz @ 76 db couple of bumps at around 60Hz but only a couple of db out. The acid test is trying a film. But the graph tells me its definitely going to be an improvement. I can now talk with confidence on the subject of Ultra / BFD calibration.