Does the first reflection point actually matter??

@erik_squires, It has been my experience that treating the first reflection points from the sidewalls in a narrow (14') room makes an enormous difference in imaging.   But I didn't get this using "normal" absorbing panels such as GIK monster traps.  What actually worked really well was a pair of 5' tall CD racks, positioned so that the front edge of the rack is angled out from the wall.  The front edge of the rack is positioned slightly to the rear of the first reflection point.  Apparently, the front edge of the racks are reflecting the higher frequencies from the tweeter and midrange back towards the front of the room.  Thus, reflected frequencies higher than 1500 Hz are blocked from a direct path to the listening position.  They are either directed behind the rack or directed back to the front of the room, thus delaying their arrival at the listening position enough that they do not compromise imaging.  

When the CD racks are removed from the room and I attempt to treat that same sidewall area with GIK products, the image collapses.  If I move the speakers enough to change the sidewall first reflection point, the image collapses unless the CD racks are removed a similar amount.  I've also noticed that depth and width of image is somewhat eroded by using GIK 242 or 244 type panels on the side walls forward of the CD racks.    

Note that this is not another ill advised attempt to use a partially filled CD rack as some sort of diffusor. 

My son did something similar in his room using bookcases, and he reported a huge improvement in imaging. 

Folks who have wider rooms will probably benefit less than those of use who listen in narrow rooms. 

BTW Eric, you seem to only be concerned with 1st reflections off the outside side wall. Don’t forget the effect of 1st reflections off the back wall, floor and ceiling. All important I think. Also consider the propriety of using the LE/DE methodology in setting up your room. When using box speakers I’ve always found a LE/DE set up (or something close to) best.

IMHO, this subject is almost as complex as rocket science due to the fact that the the results of set up and room treatments, most all of the sound folks hear is subjectively judged. Not a bad thing in itself but due to divergent expectations hardly a scientific approach (if one could even be heard). FWIW, I find it interesting reading recommendations for room corrections. Especially corner traps to improve low bass. Folks should look at an anechoic room and see what is really involved in setting up control of bass waves. Makes one wonder about ’bass traps’ typically recommended.

But to answer your original question, Yes 1st reflection points do matter and how you deal with them (not ’treat’ them) is very important if your goal is to obtain clarity and well developed 3 dimensional imaging. IMHO anyway.

YEs, the goal of treating 1st reflection points is typically to safeguard against early reflections which smear the soundstage and negatively impact imaging but can also be used to change teh balance of direct to reflected sound which directly affects soundstage and imaging.

This brings up a great topic, diffusion is better for imaging than absorption. :) 

Two different but similar things. YMMV with each.  Diffusion would serve no purpose with omnis like Ohms.   More directional designs, like my Kef ls50s in the next room, yes.