Does the first reflection point actually matter??

Personally I never quite understood the idea of the "first reflection point", but simply deferred to popular opinion. If speakers generate sound in a cone-shaped pattern in both horizontal and vertical planes, then why is the first reflection on the adjacent wall any more impactful on SQ than the first reflection point anywhere along the edge of the sound wave.

Because acoustic equations ask for some origin point in space and time...

But sound is not reducible to physical linear waves equations only, like many other phenomenon....

« The ears speak» -Groucho Marx

then why is the first reflection on the adjacent wall any more impactful on SQ than the first reflection point anywhere along the edge of the sound wave.

Because of the timing aspect.....

But i created my room acoustic without being slave to  an equation, on the contrary not obeying to the sound wave, i decide to command to the sound wave... This is active device controls of the room....

I used a lot of formulas but a simple one that gets you 'good enough' to start from is 1/5 from the sides walls and 1/5 from the back wall.  I got best imaging closer to the back wall and a little further from the side walls. Start with best speaker/audio rack placement and no acoustic support...get the best sound and then move on to the surfaces.

@tony1954, we are more sensitive to localization clues in the horizontal plane.  Most of us have our ears mounted on the side of our head, not the tops and bottoms.  :)   So early reflection points on the side wall tends to be most impactful,  Back walls that are close to the main listening position can also be more impactful in terms of confusing localization clues.  In certain cases where a room is very wide or where the main listening position is well removed from the rear wall, floor and ceiling can be more impactful.  Conventional wisdom is that you would like to have all reflections arriving at the ear with a delay of 5 to 20 milliseconds down 20 dB relative to the direct signal.  Reflections arriving at the ear within that window tend to smear the localization clues provided by the direct signal.  Reflections earlier than 5 ms tend to merge well with the direct signal, and those reflections arriving later than 20 milliseconds tend to be perceived as separate echos adding to the spaciousness of the room. 

@gs5556 ....the Yarlung site was a fun listen with my diy Walsh, which already project a large soundstage by themselves. *S*

'Sonic holography' took me back to when I owned a Carver C9 Sonic Holography Generator back in the '80s'....It didn't work consistently with everything; whether this was due to the mixing, the format, my space and placement within....

....but, when it did....you almost felt you could grab the neck of the lead guitar...;)

1st reflection with omnis (or, for that matter, dipoles) becomes either a moot point or the 'sticky wicket'.  When 'all', or nearly, becomes reflection the room becomes part of your 'system'.  It can't be ignored.

My current space is so ghastly that all I can do is to reference the late Linkwitz and 'ignore the room'.  This consists of running 5.1; F & R, L & R, with a sub 'up front'.  Works best with 4 identical drivers in the corners....

I can add a slight delay to the back pair which can enhance, but it becomes 'selection dependent' and a PIA to do. *L*

But then I'm 'listening to the stuff' rather than 'listening to the music', which kinda defeats the goal of it all....and I'm pretty atypical in approach, anyway....

Best, J