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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
audiokinesis
2,751 posts
 
"You could easily circumnavigate the laser point and it would be much much better than merely putting panels on that point."

I don’t think I’ve ever advocated a "reflection POINT" paradigm; I think I’ve been talking about a reflection ZONE.

"And that unless you are in a small home recording studio, where you can touch the left and right walls at the same time, the correct placement being off 6" here won’t matter."  

Are we actually within six inches of agreement?

Duke
brownsfan
1,508 posts
 
Imo there is an alternative approach which starts out with the design of the loudspeakers themselves, and which does not call for anything remotely approaching treatment of entire room surfaces in order to get good results. Briefly, the loudspeaker sends spectrally-correct energy in directions which minimize early sidewall reflections, and the reverberant energy is allowed to decay more or less naturally, perhaps using diffusion, as opposed to being rapidly absorbed. If anyone is interested I’ll go into detail.


@audiokinesis , I’m very interested in what you have to say on this, so if you are so inclined, please elaborate. Not that I want to distract you from completing my Swarm! ;>)
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
1,451 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.
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