Does the first reflection point actually matter??

hsw, I'm only going to answer for myself here.  My understanding is that humans are naturally more adept at localizing sources in the horizontal plane.  Our outer ears are mounted on the sides of our heads and aren't especially well designed to pick up vertical clues.  Presumably, our brains are similarly well suited for localization of sources in the horizontal plane.   What I can tell you is that in my room, which is 14 ft wide with 8 ft ceilings, effective "treatment" of the side wall 1st reflection point is orders of magnitude more important than "treating" the ceiling and floor 1st reflection points in providing a deep and wide image with good localization of instruments and voices.  My floor is not carpeted, and my ceiling is typical texture over drywall.   I'm not going to say that rugs and room furniture don't matter, just that in most rooms, treating the floor and ceiling don't matter nearly as much as treating the side walls with respect to imaging.  If you have a room that is atypically wide, or speakers that don't have wide dispersion, you may see something different.  Also, what you do with the floor and ceiling can certainly impact other aspects of room performance.  Floor to ceiling bounce can be a big contributor to slap echo, as example. 

@erik_squires, have you tried what Duke is suggesting on the sidewalls?  I stumbled onto this idea of redirecting the sidewall 1st reflections to the front of the room several years ago quite by accident.  Every attempt on my part to reproduce the benefit of redirecting by using absorbance has failed.  The image just collapses.  Had I not experienced just what this technique can do myself, I might be arguing as you are.  

Floors are a different thing, but we don't spot treat floors.  We treat the entire area in front of a speaker. I've never seen anyone put down a 2'x2' carpet exactly in the first reflection point, and this is kind of what i mean.

Audiophiles at some point were encouraged to use a flashlight and mirror to find first reflection points and center acoustic panels there. I call that particular practice bunk. 

We shouldn't spot treat surfaces.  We should treat the surface.  That is, putting 2'x2' panels in exactly the side, rear and even floor reflection points is practically useless. What does work is to treat the floor, side and rear.

Get a carpet to put in front of the speaker, treat the side walls and rear wall and wall behind the listener. Where the mirror points are won't matter.

Best,

E

Erik wrote: " We shouldn’t spot treat surfaces. We should treat the surface. That is, putting 2’x2’ panels in exactly the side, rear and even floor reflection points is practically useless. What does work is to treat the floor, side and rear. "

So if I understand correctly, you are saying that treating the relatively small area where a reflection occurs is "practically useless" - instead, we should treat the ENTIRE room surface - the entire wall, or the entire floor, and/or the entire ceiling.

Am I understanding you correctly?

And, just so we’re on the same page as much as possible, can you describe what you mean by "treat"?

Thanks!

Duke

So if I understand correctly, you are saying that treating the relatively small area where a reflection occurs is "practically useless"

Yes, in that I believe most audiophiles would be unable to tell if those treatments were at the reflection points or not, and that in many cases 4 panels of 2'x2', no matter how well placed, would be unable to effect an audible improvement.

And, just so we’re on the same page as much as possible, can you describe what you mean by "treat"?

By this I mean to alter the surfaces by increasing the absorption and decreasing the ability of those surfaces to throw a coherent reflection by both absorption and diffusion.



Best,

Erik

Let me try this another way. Imagine a highly reflective room with a pair of traditional 2 way speakers and 1 listening chair in a fixed location. The room is 20’x20’x15’ tall.

There are at least six (eight if we include the ceiling) first reflection points. Being points, they are infinitely small. The audio legend is that these specific points are more important, by far, than any other place in the room. In this room we may place 1’x1’ absorptive panels.

My argument is that the legend/myth is wrong. The first six reflection points are not going to be noticeably better than any other place to put an absorber or diffusor.

Lets go through a bit of a mental exercise. We’ll consider two sides to this.

First, the very sparse case in which we treat six points and only those. At six absorbers the room remains too lively to make much of a difference.

Let’s consider the opposite situation. We have 40 panels of the same 1’x1’ dimension. Now we can make enough of a difference in the reverberant field to affect the sound quality. We put 20 or uniformly spread across the wall behind the speaker, and 10 on each side on the speaker end.

Let’s say by chance, four of these panels (2 on the rear, and 1 on each side) are exactly on the first reflection points in terms of the listening chair. In this case, removing those four panels and randomly relocating them will make a very small, if any, noticeable difference.

And this illustrates my point. Treating the initial reflection points is actually not as important as treating the room. The audiophile using a mirror to place a panel exactly on that spot is wasting his/her time.  What is more important, by far, is getting a critical mass of room treatment so that the reverberant field becomes well controlled.