Originally Posted by mogorf
You are receiving good advice from very experienced members here.
Here's one more tip for today.
Although you did not describe your room and the positions of surrounds in the room, but if you have a chance you may move your surrounds closer to a side wall or even to a corner. By this way you can make use of a phenomenon called "room-gain" resulting in extending the low frequency output of a speaker. Re-run Audyssey and check the crossover. Report back please.
Very much appreciate the advice here. The surrounds are positioned 6.5 feet directly to either side of the main listen position. The front line is 10 feet away and the subs are equidistant at the sides, also 6.5 feet away (see below). Unfortunately there is no wall close at the right side enough because the room opens to the hallway/entranceway on that side. I experimented with lowering the crossover frequency to 150Hz for the surrounds and played "Kind of Blue" on CD using the Marantz multichannel stereo mode to put as much information into the surround channels as possible. This recording features a lot of subtle bass walking lines which cover the area of interest here and I think that lowering the crossover to 150Hz fills out the bass a little bit and did not seem to localize it. Very small difference overall, difficult to really pick it out by ear, but I am going to leave it set to 150Hz for now.
The room is 17' by 33' with a high cathedral type ceiling.
Equipment is as follows:
Marantz SR5008 AVR
Panasonic DVD/CD source (generic/older unit).
NHT Classic Absolute Zero FL/FR
NHT Classic Absolute Center C
NHT ST4 (top section) SL/SR
NHT ST4 (bottom section) SW1/SW2
The ST4s are tower speakers with completely discrete chambers for the Mid/Hi top section (1"/6.5") and the sub section (8"). I am using a Brytson 4b amp for the subwoofers, 250wpc. [I know that is a bit different - I really like these speakers.] The ST4s are biamplified, obviously, but they retain their passive crossovers set at 135Hz whether you biamp or biwire.