CLS side wall reflection points

Given the 30 degree dispersion of the CLS panel do the sidewall reflection points need to have wider/narrower treatments applied to account for the dispersion pattern of the CLS panel?

I find that as I account for side wall reflection points as I move across the sofa using the mirror approach I'm going to end up with 2/3rds of the side wall covered in treatments to cover all the reflection points from the sidewalls, but if I only account for the sound that I think is hitting the sidewalls given the 30 degree dispersion then I end up with a smaller area to treat. Of course I could narrow it further if I only accounted for my seat.

Unfortunately I don't have extra panels hanging around right now and I'm curious what your experiences have been with rectangular rooms.

I haven't really tried side wall reflections yet ! Its something I want to play with ! The CLS are so good at wide reflections that they are the only ML speakers I use NO toe with. The Key I think is to get them out in a room and away from the side wals at least 2 feet.

In my room 15x24 when I set in the sweet spot there were reflection on the sides. The right side had a large picture with glass in the frame the left side had windows with wooden louver blinds covering. I would, with some music more than others, hear reflections from the sides. The frame and glass more than the other seemed to be the more noticeable side .
When I listen to music I place 2'x6' from 2" thick Owens Corning 705 at the reflection points. It is easy to see them in the glass.This worked very well to cure the problem.
As for other seating positions I don't bother since I am the only one that listens to music.

sidewall clearance and sidewall reflections

These are two different things:

1.) The reason for the 30" (minimum) clearance between the outer edge of the speakers and the sidewalls is to allow the rear waves a path into the room instead of being bottled up behind the speakers and possibly even interfering with the movement of the diaphragms themselves (letting the speakers "breathe".)

2.) Sidewall reflections result when part of a widely dispersed front wave hits the sidewall and (possibly) gets reflected back to the listening position. I say possibly because if you are listening nearfield (close to the speakers in a narrow room) these reflections will pass behind the listening position and will not be heard.)

A second possibility is that these secondary (sidewall) reflections do get to the listening position but that they arrive too late (in time) to screw up the image. Psychoacoustic studies have determined that if the secondary reflection arrives 5 milliseconds (5/1000 sec.) or more after the direct (first arrival) wave, the brain reads it as an echo and no harm is done. Less than that and the first and second arrival waves are combined by the brain and the image suffers.

A sound wave travels about 6 feet in 5 milliseconds, so if the total path length of the sidewall reflection is 6 feet more (or longer) than the length of the first arrival wave's path, again there should be no problem. There is a small range of configurations that will require absorbtion on the side walls; but seeing your speakers in a mirror is only part of the test. Measuring the path length of the secondary reflection is also necessary.

Google will provide you with endless reading on this subject.

Thanks all

nsgarch said:

Google will provide you with endless reading on this subject.

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Agreed

I've used the Google extensively, is there anything special I should take into cosideration with the CLS panels and the front wave? I'm guessing not.

JohnLomnicki said:

, is there anything special I should take into cosideration with the CLS panels and the front wave? I'm guessing not.

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Yes there are a couple of things. First, get them up on stands. Sound Anchor http://www.soundanchors.com/page24.html makes a pair custom designed for the CLS. Chris (C.A.P.) just built a nice pair based on the (no longer made) Arcici design, but he has the welding skills The other thing that's really important with the CLS's (and probably all panels) is that they both be adjusted exactly the same relative to the centerline of the room and to each other. I use a 24" carpenter's bubble level with a built-in laser.

As Neil stated , EXACT placement is crucial. Look at my last 1% thread and its that detailed. This will make or break a CLS set up. They are that revealing. But its all worth it as you get a sound stage that is unlike any other.

JohnLomnicki said:

Unfortunately I don't have extra panels hanging around right now and I'm curious what your experiences have been with rectangular rooms.

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I have found 1st reflection point treatment along with treatment next to the speaker (side wall) has had a great improvement for me.

I have used 2" bonded acoustical cotton for my homemade panels. Here is a post about them:

http://www.martinloganowners.com/~tdacquis/forum/showpost.php?p=77668&postcount=6