Early reflection panel thickness... - Page 3 - AVS Forum
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post #61 of 67 Old 03-26-2012, 05:44 AM
 
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Floyd Toole:

"Some people come to this topic thinking that, as is some other things, that there must be a simple way to do acoustical design, a kind of cookbook, that anybody can understand. I wish that were so, because it would simplify all of our lives. As it is, achieving truly good sound in rooms requires knowledge of how sound behaves in rooms, and some effort – or more than a little bit of luck."
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post #62 of 67 Old 03-26-2012, 06:11 AM
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no improvement < some improvement < more improvement < perfection

somewhere along that path is a happy medium where physical constraints, budgetary constraints, and desires can come together (and leave an upgrade path). Sometimes the best that can be done is to pick the low hanging fruit and come back later and play in the weeds.

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post #63 of 67 Old 03-30-2012, 01:34 AM - Thread Starter
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Thanks Dennis
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post #64 of 67 Old 04-01-2012, 09:41 AM
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Quote:
Originally Posted by Digital_Chris View Post

So, my OCD kicks in and I end up doing SO much research on every aspect of my theater, it is overwhelming, to the point of finding contradicting evidence. What I have researched the most is how to treat early reflections and bass peaks/nulls. So much that I have found some ppl say 1" thick is plenty to calm down those reflections, others say 2" is a minimum and 4" is better, on top of that, space it away from the wall, yadda yadda.

Now, I am almost ready for drywall and have a few ideas on how to treat my early reflections. My first plan was to cover all walls with fabric panels, something like this... (IE wouldn't show the lines in between each panel correctly, try to picture 12 panels there)

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Each wall will be covered with 1" fabric panels, and I will have OC703 or equivelent behind the "problem" areas (found using the mirror trick). This way, you won't be able to see the reflection panels. Now, since my room is small to begin with, I can't afford to loose too much more, if any, space.

I would like your opinion on whether or not 1" thick absorbtion will be "good enough" for the early reflections or if 2" or larger is DEFINITELY the recommended. If so, I will have to do some funky in-wall panels, but trying to keep this simple. I will also be treating the rear corners with superchunk style bass traps. I know the thicker the panel or more space behind the panel, the lower the frequency it will take care of, but, I just want to make sure I'm getting good imaging and front sound field without going completely overboard.

Also, I'm not trying to make the room a perfect sounding room, that would drive me CRAZY trying to figure that out. Instead, just the main problem areas (early reflection points and corner bass).

Thanks

If you can leave some of the drywall off, and you don't mind the loss in sound isolation, you can pick up a few more inches of absorber depth by recessing them into the walls.
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post #65 of 67 Old 04-01-2012, 10:41 AM - Thread Starter
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Sorry, I'm way past that part, drywall has been up for quite some time now. Thanks for the suggestion though.
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post #66 of 67 Old 02-22-2014, 05:35 AM
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There is a lot of good discussion in this thread, I suggest those in the process of building their HT read it and digest it.
To help visualize, this graphic may help
Acoustic%2520treatment%2520material%2520plus%2520airgap%2520explain.jpg

want to add this link also, via Ethan W site, read that link for more details:
http://ethanwiner.com/acoustics.html#air%20gap
Quote:
OPTIMIZING THE AIR GAP

While increasing the depth of the air gap does indeed lower the frequency range absorbed, for thinner panels it can also reduce the absorption at some higher bass frequencies. The maximum amount of absorption for a given frequency occurs when the air gap is 1/4 the wavelength for that frequency. Figure 4 below shows the velocity of a sound wave, which is greatest as it transitions through zero. When it reaches the top or bottom of the cycle, the velocity is minimum, but the pressure is maximum. Because the velocity is greatest 1/4 wavelength from a boundary, more energy is present to force the waves through the absorbent material.
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post #67 of 67 Old 02-22-2014, 08:12 AM
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Quote:
Originally Posted by mtbdudex View Post

There is a lot of good discussion in this thread, I suggest those in the process of building their HT read it and digest it.
To help visualize, this graphic may help
Acoustic%2520treatment%2520material%2520plus%2520airgap%2520explain.jpg

Thanks for reviving this thread. Even though the OP may be long gone/done, it's a good topic to keep in mind!

I like the chart and table you shared.

What does the impact look like if one moves beyond 4" panel and 4" gap?

For example, I'm building a false screen wall and other than where the speakers are, I could have 4" panel and 12" gap.... if that helps get down into lower frequencies.


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