ATC SCM19 V2 Recommendations.

I recommend buying s Sound Pressure Meter

Set it up on a tripod, ear level, listening position. 

Then play test tones, measuring spl of each tone. Find best arrangement.

Generally, tilt back so tweeters are aimed at seated ear level. Then toe-in so speakers are facing you directly. Both alter the angles of reflection regarding floor, ceiling, side walls.

Alternate toe-in for listening with a friend. Aim right speaker at left chair; right speaker aimed at right seat. This gives fairly good imaging of both sides and center. Closer to the speaker your side's volume, but more direct radiation/volume from other side, works!

I have this test disc

see track list, 1/3 octave test tones. It's gotten very expensive, I could probably find a less costly copy.

Other test discs exist, just gotta search. Any suggestions from others?

@elliottbnewcombjr 

Thanks for the tip.

I actually have an older RadioShack SPL around somewhere and I think Tidal has some test tones available.

At the moment I am doing some research into long wall placement using the Audio Physic guide. I recently switched my room layout 90 degrees. I was just sick of dancing through my speakers to get to my patio, but the reduced available distance has its challenges. Things like having a coffee table or the placement of the bass array.

Equilateral triangle, as far from side walls as possible, use sound anchor stands (ADJ 2’s for variable height or the shorter 3 post fixed height model). That will get you started. Your iPhone has SPL meter apps available. Pink noise is useful for walk testing your space, you hear how the position changes the balance from bass to no bass, rolls off high end, boosts high end, etc. Very easy to hear how pink noise changes character with position to speakers vs those changes in music with position.

Remember it’s the direct vs reflected energy ratio that affects the sound of things. The more direct sound the better, the more reflected sound the worse. You get into a triangle small enough to raise the level of direct over reflected energy. Panels and treatment can expand the size of the triangle.

OP, @lonemountain is an ATC rep, take it from the horses mouth and follow his recommendation to the T before doing anything else.