Room Treaments - Where To Begin...

15 years ago, the realtor had a funny look on his face when I was walking around the new house, with furnishings, and occasionally clapped my hands or even whistled. Before the wife moved in, I was able to try out a few arrangements for speaker placement and a listening position as well. Paid off as good as it could given the circumstances. 

 Now days, when she leaves for work, I can adjust the furnishings in the room to better suit the result.

Good answer from MC. If you can't start there you will never get started.

A good quality equalizer is great for correcting room anomalies. 

I am an engineer with experience in acoustics, though mostly in the field of explosives (don't ask or ----).  Equalizers or DSP do not solve your room problems, altering your room solves or helps with your room problems. The first question is what is the problem.  In my current room it was a massive bass problem, in the end I built 2 very large bass traps (1.5 x 0.8 x 0.8 m). These help enormously, any smaller made little difference.  I also use 2 subwoofers which help with balance. 

  Now wouldn't that be a cool job and quite a challenge. "What? I didn't hear anything."