Originally Posted by jayray
The Sigs and Studios like being up to 3 ft. Away from the wall. My studio 100s did the same thing.
Studlygoorite and jayray make an excellent point.
Placement is very important to speaker response.
I looked at your pictures of your HT and it looks like the mains are in recessed alcoves which may be causing the problem you are experiencing.
In ARC, under 'tools' there is a very useful option called 'quick measure'. If you are not familiar with it, it allows you to run sweeps on one speaker at a time. It has been very helpful to many of us here in finding an optimal subwoofer position, but in your case it should help you find a better spot for your fronts.
Start it with LF and see what it looks like. Since you haven't posted your charts I can't be sure, but I guess there's a pretty big dip thats causing ARC to set its crossover so high.
Move it out a little from the wall and see what happens in QM. Keep moving it around until you get the best response possible.
Switch the QM to RF and repeat the process. Chances are its optimal position will mirror the RF.
If you have any other speakers that need their position tweeked (especially the sub) you can do that also while running QM.
Once their distance from your back and side walls is determined you may want to tweek the toe in of your fronts for optimal imaging (after you've run QM, but before re-running ARC.) Be sure that 'room eq' is turned off for the source you use to test your imaging.
You will of course need to re-run ARC after moving the speakers, but you should get a much better solution for your speakers.
This takes a little time, but will be well worth it in sound quality.