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Does the first reflection point actually matter??

Hello my friends,

So please read the whole post before commenting. The question is nuanced.

First, as you probably know I’m a huge fan of the well treated room, and a fan boy of GIK acoustics as a result, so what I am _not_ arguing is against proper room treatment. I remember many years ago, perhaps in Audio magazine (dating myself?) the concept of treating the first reflection points came up, and it seems really logical, and quickly adopted. Mirrors, flashlights and lasers and paying the neighbor’s kid (because we don’t have real friends) to come and hold them while marking the wall became common.

However!! In my experience, I have not actually been able to tell the difference between panels on and off that first reflection point. Of course, I can hear the difference between panels and not, but after all these years, I want to ask if any of you personally know that the first reflection point really matters more than other similar locations. Were we scammed? By knowing I mean, did you experiment? Did you find it the night and day difference that was uttered, or was it a subtle thing, and if those panels were moved 6" off, would you hear it?


Best,


Erik
erik_squires
mijostyn's avatar
mijostyn
8,570 posts
 
20% is a huge amount of wall area. First of all, the area you treat is going to depend on a number of variables like how big the room is, were your listening position is relative to the speakers, the type of speakers used, etc. Only 4% of my front wall is treated. 

Brownsfan, I mention this above. Speakers with limited or controlled dispersion patterns will require less treatment than speakers that are omnidirectional. They will have fewer early reflection points/zones.
Examples are horn speakers, dipoles and line sources. 
mijostyn's avatar
mijostyn
8,570 posts
 
It is easy to absorb frequencies down to about 250 Hz. If one does not get overly aggressive with the treatment the spectral balance of the sound will not shift much. For those of us with full spectrum room control it does not matter as any shift can be easily corrected. 
antigrunge2
1,450 posts
 
This is a great thread,

may I suggest that moving speakers into a near-field listening position, i.e. far away from the walls or using omnidirectional speakers is a better way to address the issue than selectively cutting out some reflections and parts of the frequency spectrum. If needed, bass traps in the corners of the room are obviously useful.
erik_squires OP
16,375 posts
 
There really is no issue in my mind to be fixed. 

It's more of a theoretical discussion. 

Maybe another way to word it is this:

You can't do much with room acoustics until you reach a critical mass. 4 2' x 4' panels in a modest living room are probably not going to do anything by themselves no matter how well placed.
optimize
164 posts
 
I saw a interesting video about carpet and first reflection floor points.

Here is a myth to bust!

The carpet that we can see as a thin sound absorber do NOTHING to the first reflection point on the floor.

Instead what the carpet do is that it absorb only/mostly the high frequencies instead from 2nd and higher order of reflection.

Something to keep in mind. Look at the graph in the video:
https://youtu.be/GpDHo1jNhss

This example with thin carpet shows that we should always go for the thickest absorbers that we can get.
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