Does the first reflection point actually matter??

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.

@erik_squires , 

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. 

Eric, I have a dedicated room.  I made 2'x4'x4" OC 703 panels that cover first reflection points on both the floor and ceiling.  The rest of my floor is untreated.  I realize this is not common, but I have a dedicated room and I am the only listener, so I can do what I want.   Both ceiling and floor "treatments" have very little influence on imaging in comparison to my side wall "treatment."    They certainly offer other benefits. which more than justify their use.  I have considered modifying my ceiling panels in order to add forward facing reflection to the existing absorption, but have not done so yet. 

As I recall, my measurements show that the floor and ceiling reflections are delayed about 4-8 ms, whereas the side wall reflections are more in the 6-12 ms range.   Without treatment, the ceiling and floor reflections are louder than those from the side walls.   With treatment, the side wall reflections are substantially reduced, whereas the ceiling and floor reflections remain relatively high.  To a certain extent, I think this is indicative of how much more effective reflection is compared to absorption.  

From my perspective, sidewall 1st reflection point treatment is conceptually sound, and in my room, theory has been supported empirically.  Imaging and localization in my room is superb.  It is the best by far that I have ever heard in a narrow room.  If you have experienced something different, perhaps that is because you are attempting to "treat" your sidewalls using panels that are not up to the task.  Again, I'm going to suggest that before you discount the concept, you evaluate the approach articulated at least twice by Duke and several times by me.   Rip a 4x8 sheet of half inch plywood into 2 x 8 sheets and place them along the side wall behind the first reflection points angled so as to reflect sound back to the front of the room and away from the MLP.  This is enough to reflect the wavelengths that are important to localization clues, and it turns early reflections into late ones.  It is a cheap and easy experiment.  Keep in mind that the first reflection "point" is far from a point, because the sound coming from your tweeter and midrange will spread out as it travels rather than proceed as a laser like ray.  So you will need to experiment with placement and angle.