[Blueeyedfrog]

Ok, I made a kind of wall out of the shelving and placed it on an angle, widening out from the top wall. I think generally with the mains/surrounds the sound is better.

The top graph shows the response for the sub with the new 'wall'. Little improvement - still a big range from peaks to lows; 42db. The bottom graph is with the sub in the bottom right corner behind the listening position. Much flatter, but still 32db between peak and troff. The rear position also drops more than the front position(s) near 20-21hz (about 9db on avarage).

Subjectively, the sub bass seems somewhat quieter with the sub at the rear, but still shakes the seat when required. I think it's better (not sure) - less intrusive? More balanced? It doesn't seem like the bass is coming from behind though, which is good. At present, as per usual, all the speakers are same db using receiver's pink noise. Should I just try to get a balanced curve and then turn the gain up on the sub to compensate?

Anyway, is the rear a better position to start from? If so, which should I try first, eq-ing or bass trapping?

Cheers,
Blue