moth076:

Is only the wall on the back side of the speaker that has the adverse acoustic effect, or the side walls have an impact, as well?  When having speakers close to the side walls,would turning them inward a few degrees help?

I will push the shelving unit closer to the fireplace, put the spikes on the towers and try to reposition everything away from the walls... 

Thanks! - I appreciate your feedback.

As for the spikes, besides support and protection, are they being recommended for any other reason?

 

Kris 

Yeah, at least two feet from the side walls would be ideal maybe you can bring the left tower forward so it's on the same axis as the right tower and then in a little bit so it is in front of the left leg of the stand.  If you don't use that fireplace I'd put the right tower right at the outer edge of it and at least a foot in front of it to get a little clearance from the walls.

The floor spikes decouple the sub from the floor and should give it a tighter/cleaner sound.  Same thing with the spikes for the towers.