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Acoustical Treatments Master Thread - Page 328

post #9811 of 10203
Quote:
Originally Posted by coolgeek View Post

Would placing cork material around the entire walls be a good idea?
What is the acoustic issue you are trying to address here?


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post #9812 of 10203
Quote:

Your room looks really nice.
Have you taken acoustic measurements?
If so, post them for understanding of what you are trying to accomplish per your earlier post.


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post #9813 of 10203
Quote:
Originally Posted by mtbdudex View Post

What is the acoustic issue you are trying to address here?


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Right now it's basically a concrete bunker. Lots of echo. Someone told me to plaster cork all around as first phase of my treatment... not sure what cork does...
post #9814 of 10203
Quote:
Originally Posted by coolgeek View Post

not sure what cork does...
Not much. skip it. Measurements would help.
post #9815 of 10203
Quote:
Originally Posted by HopefulFred View Post

Not much. skip it. Measurements would help.

Thanks.
post #9816 of 10203
You don't hear of people really using cork much (not saying that some people don't), but it is hard to fix things without accurate readings and testing. Of course, there are some things that can help using some general guidelines for all around acoustics. Check out these videos from AVS's content director Scott Wilkinson....

Acoustics 101




Acoustics 102
post #9817 of 10203
I used cork for my DIY dartboard backing wall zone:


and my wifes craft room flooring


so it's nice to walk on, with the 3/4" thick underlayment, and good for stray darts.....

As acoustic treatment, well it will reflect the above Fs freq mostly, so won't help with any specular reflection management, and will do nothing for LFE bass management / modal ringing either.

HT Acoustics 101:
Why: Psychoacoustic studies, then application of those results have revealed that properly applied acoustic treatments can improve you subjective listening experience

What: Understand and manage the room/speaker/listener interaction to provide the "best" listening space
Where: first reflection points are good starters, and for bass / LFE modal ringing issues corners/wall intersections are good places also
How: depending on speakers/layout/room interaction and other factors, absorption and/or diffusion can be utilized
>>Key is attacking the issue, and not over absorbing if applying absorption, also absorbing across the spectrum - ie - not too thin or you will be applying an acoustic "filter" and color the sound

btw coolgeek, your build thread indicated that GIK and Bryan was hired already, so...... ????
Are you not liking their recommendations or what???
http://www.avsforum.com/t/1482805/coolgeeks-concrete-bunker-home-theater-build/60#post_23798198
Quote:
Originally Posted by coolgeek View Post

.......

Right now, I have hired Bryan from GikAcoustics to help me design the treatments i'll need.

I am thinking at least 6 months down the road...

...

Edited by mtbdudex - 11/18/13 at 9:59am
post #9818 of 10203
I have a question was thinking of doing this besides corner bass traps.

In the picture below to the right and left of my screen are open wall space. Along the left and right side of the walls I built out panels Without insulation but more to absorb reflection.

Can I just put Roxul behind those panels and do the whole wall to the left and right of thee screen?

post #9819 of 10203
Quote:
Originally Posted by Holiday121 View Post

I have a question was thinking of doing this besides corner bass traps.

In the picture below to the right and left of my screen are open wall space. Along the left and right side of the walls I built out panels Without insulation but more to absorb reflection.

Can I just put Roxul behind those panels and do the whole wall to the left and right of thee screen?


Do you have SBIR issues and want to tackle them?

Putting absorption just anywhere should not be done, unless for a specific purpose based on some plan.
post #9820 of 10203
I have no clue honestly. I'm just going by some layouts people use mostly.

Is their anyway a complete noob can figure out where treatment is needed
post #9821 of 10203
Quote:
Originally Posted by Holiday121 View Post

I have no clue honestly. I'm just going by some layouts people use mostly.

Is their anyway a complete noob can figure out where treatment is needed

sure - break up the sound into above the Fs and treat the first reflection areas for your front sound stage mains RCL.
Do that as minimal as possible, don't over absorb. The mirror trick works for that.
http://realtraps.com/rfz.htm
It's best if you have a measurement mic to guide you, if not, then apply at least 2" of OC703 (or similar) + 2" air gap for your side wall panels.

If you apply just 1" of some acoustic material directly on side walls you will EQ your sound, not fully absorb it to the Fs.

More here:
http://www.avsforum.com/t/1312693/diy-construction-methods-of-hang-able-acoustic-panels-not-fixed-frames#post_19947420
Quote:
Side note:

I have this general suggestion for those wanting to learn about acoustics:


A) read this Acoustics/Treatment Reference Guide , via gearslutz, its a easy read in layman terms, starts you off with basics and good foundation with practical discussion. Studio acoustics and Home Theater acoustics.

From that, simple/straight forward advice via Jens Eklund:
Quote:
1. Learn how to make measurements: REW - Room EQ Wizard Home Page

Don’t do anything without measurements.


2. Define your MLP (Master listening position). Confirm with measurements.

(Mike R modified for HT viewpoint)


3. Identify and treat your modal and SBIR - Speaker Boundary Interference Response related issues and educate yourself about different bass-absorbing techniques.

Other info: SBIR by Bryan Pape


4. Treat areas that otherwise creates early reflections.


5. If the room is big enough, add diffusers (but read up on how to use diffusers before going nuts).


Always base your decisions regarding different treatment, on measurements. Avoid thin porous only absorbers (including wall to wall –carpet, drapes etc.) unless a measurement indicates the need for it.

B) Knowing that for “best” audio/sound in a listening room, these parameters are tackled in prioritized order:

1. Speaker location, 2. Listener position, 3. Acoustic treatments, 4. Electronic correction.

Understand the small room acoustic model you will follow.

Looking at this link, everyone can see visually the various small room models, it's 7 pages from the book "Acoustics and Psychoacoustics Applied"
http://eetimes.com/design/audio-desi...n?pageNumber=0


C) If you have desire for more knowledge:

-read one of many books out there, a great 1st book is "Master Handbook of Acoustics" by F. Alton Everest, a perfect follow-up book is "Sound Reproduction: The Acoustics and Psychoacoustics of Loudspeakers and Rooms" by Floyd Toole.

-study Ethan Winers site, http://www.ethanwiner.com/acoustics.html

-Become familiar with the different small room acoustic models for home listening spaces

-This is also a 101 read on Room Acoustics, http://www.crutchfield.com/learn/learningcenter/home/speakers_roomacoustics.html

-SAE Home Acoustics info site has many definitions and explanations http://www.sae.edu/reference_material/audio/pages/fullindex.htm

-There are many other sites on the web, like

........One of the first ones, StudioTips small room acoustics forum http://forum.studiotips.com/index.php,

........Acoustical measurements defined Rives audio http://www.positive-feedback.com/Issue12/rives2.htm,

........RPG Acoustics Library papers http://www.rpginc.com/news/library.htm, etc.

-Be careful of info overload all at once


D) Measurement info/threads:

-online downloadable file with the Sound System Engineering chapter 6 on measurements http://www.focalpress.com/uploadedFiles/Books/Book_Media/Audio/9780240808307.pdf
-Get the hardware side of REW down quickly, this thread by member omegaslast dummy's guide on setting up REW and his blog http://polaraudio.blogspot.com/2012/01/calibration.html easy 101 read with pictures to walk you thru the mechanical of set-up and taking measurements
-Highly recommend Nyal Mellor's site, http://www.acousticfrontiers.com/Aco...surements.html , and a very detailed/helpful white paper http://blog.acousticfrontiers.com/st...ist.%20Rms.pdf

-Room Measurement & Treatment by "fotto" (Floyd)

- Envelope Time Curve - ETC - Impulse gearslutz thread

-Using energy time curve for acoustic analysis: by "mtbdudex" (Mike R)
-http://www.avsforum.com/t/1421599/etc-isd-gap-question ETC - ISD gap by

-Basic acoustic measurement primer v2.1 (via gearslutz "DanDan")

-http://www.realtraps.com/art_measuring.htm
-http://www.avsforum.com/t/1316623/diy-custom-printed-movie-poster-acoustic-panels-cheap/60#post_20147783 DIY Custom-Printed Movie Poster Acoustic Panels
-first reflection software: http://www.avsforum.com/t/822273/free-software-to-help-determine-your-first-reflection-points/240#post_22619555
[/QUOTE]
Edited by mtbdudex - 11/19/13 at 9:14am
post #9822 of 10203
Ok, I have read a lot of this thread but is there any issue with using acoustic foam panels (Sonex classic?) for front wall? I could add them over OC703, but I really like the 'recording studio/industrial' look of the foam panels (beats plain old GOM black for front wall/false wall)
post #9823 of 10203
I know that most fiberglass, rock wool come in standard size 4' x 2' panels and I see tons of picks where the new panel is stradling a corner, my question then is, is it necessary to have it 2' across or can 1' x 4' (lets assume 4" thick) work just as well? I rather have a smaller dimension in the room that is would be effective for bass as well as save where I can use the other piece to use on another corner?

Has anyone tested this?
post #9824 of 10203
Quote:
Originally Posted by mrevo2u View Post

Ok, I have read a lot of this thread but is there any issue with using acoustic foam panels (Sonex classic?) for front wall? I could add them over OC703, but I really like the 'recording studio/industrial' look of the foam panels (beats plain old GOM black for front wall/false wall)

I have just officially read the entire thread...not that I can remember all the details but some of it has stuck between my senile ears.

The issue with most foam products is lack of bass absorption. Foam comes in two basic flavors; open cell or closed cell. Closed cell will reflect more that it will absorb. Open cell will absorb more but from all that I have read here and elsewhere it still does not work as well as other products with more open internal material structures like random compressed glass fibers (fiberglass) or random compressed mineral fibers (Roxoul) or even cotton fibers. Open cell foam does not have the same structure on the microscopic level as does most fiber products. The tortuous pathway of compressed fibers creates a deeper passage from the surface of the panel for sound to enter and interact with the fibers to slow down the sound waves (absorb them) vs open cell foam which tends to have a very shallow and self-contained bubble-like structure which will absorb at the skin of the material but not so much further inside of it due to restrictions in the material itself.

I used to work the microscopic filtration so this stuff is very near and dear to my past vocation. Filtration of microorganisms is not that much different than sound waves in some respects. The fluid dynamics of water vs air is but one of the similarities.

Short answer: use a compressed fiber material; not open or closed cell foam for the best absorption.
post #9825 of 10203
Closed cell foam should not be considered for absorption (like concrete, it absorbs, just a tiny bit).

Open cell foam can be very effective. Make sure its tested and use its absorption coefficients as your guide.
Auralex sells lots of open cell foam wedges and things: http://www.auralex.com/testdata/

Wool (rockwool, fiberglass wool, and even cotton wool) is also very effective, with rockwool and fiberglass being the most effective for your $ because they are so inexpensive.
Some old comparisons at
http://www.bobgolds.com/AbsorptionCoefficients.htm
post #9826 of 10203
When building a riser is it better to seal it or could the three sides surrounded by the wall be left open and the cavity of the riser stuffed with pink fluffy to create a bass trap or is it better to be fully enclosed?
post #9827 of 10203
Quote:
Originally Posted by matthewa View Post

When building a riser is it better to seal it or could the three sides surrounded by the wall be left open and the cavity of the riser stuffed with pink fluffy to create a bass trap or is it better to be fully enclosed?

I was going to ask the exact same question because I don't really have much space for Bass Traps.. .
post #9828 of 10203
I am planning to build a thick bass trap and wrap it with black velvet (absorb reflected ambient light). Can the bass energy (sub 150Hz) goes through the velvet?
post #9829 of 10203
My theater is basically a concrete box (slab floor) with a raised floor above part of it to create a two tier riser (floor is standard residential construction with engineered joists, 1 1/8" subfloor, glued and screwed). Should area below 'riser' be filled with pink insulation (volume is over 1000 cubic feet)?
post #9830 of 10203
Quote:
Originally Posted by Skylinestar View Post

I am planning to build a thick bass trap and wrap it with black velvet (absorb reflected ambient light). Can the bass energy (sub 150Hz) goes through the velvet?
While some materials may be slightly more transparent to low frequency sound, I think you will find the difference is virtually immeasurable for this purpose. Proceed with confidence, says I.

Quote:
Originally Posted by mrevo2u View Post

My theater is basically a concrete box (slab floor) with a raised floor above part of it to create a two tier riser (floor is standard residential construction with engineered joists, 1 1/8" subfloor, glued and screwed). Should area below 'riser' be filled with pink insulation (volume is over 1000 cubic feet)?
Any enclosed air cavity has the potential to resonate and color the sound of the space. Loosely fill with insulation - the cheaper the better.
post #9831 of 10203
I went to joan fabrics today and they had speaker fabric. I was going to build me some diamond shape side panels but the fabric kinda was see through. It was black and actually called speaker fabric.

Anyone else recommend any other kind because you would be able
To clearly see through it
post #9832 of 10203
Quote:
Originally Posted by Holiday121 View Post

I went to joan fabrics today and they had speaker fabric. I was going to build me some diamond shape side panels but the fabric kinda was see through. It was black and actually called speaker fabric.

Anyone else recommend any other kind because you would be able
To clearly see through it

I used that exact same speaker grille fabric and not an issue
http://www.avsforum.com/t/1312693/diy-construction-methods-of-hang-able-acoustic-panels-moveable-corner-traps-not-fixed-frames#post_19947600
Quote:
Originally Posted by mtbdudex View Post

Wrapping fiberglass 101, it's itchy be careful!


Cut to size, my speaker grille fabric came from Joanns, 60" wide, I bought 15 yards, $8/yard with coupon normal $9.99/yard.


wrap a side and pin with 1 3/4" pins, angles to stay in from tension.


Complete the wrap, it's my first time, got decent at wrapping and pinning.

Went real quick w/o mess.



Frontside mounted.............Backside mounted (after stained the frame)
.

_MG_5035.jpg
post #9833 of 10203
Quote:

Mike, I love your cloud acoustic panels!
post #9834 of 10203
So I've tried this question in various ways in a few other sections but to no avail.

Martin Logan ESL or Theos electrostats behind a very fine AT screen. About 2.5 feet from side and just over 2 ft from back wall. Used mostly as a dedicated theater but with some stereo as well. Due tot he Electrostats being a dipolar speaker and having the front wall treated, what might I expect, and are there any ways to make adjustments to make it work. I will have an audessey multiEQX32 mic to use for setup if that mkes a difference.

Any feedback would be amazing at this point.

Edit.

This is whats on ML's website... towards the end it perhaps could suggest maybe depth of soundstage would be the only posisble compromise? To what degree?

Another key attribute of the ElectroMotion ESL is its naturally dipolar radiation pattern. A true dipole, The EM-ESL radiates sound with equal intensity from the front and back of its diaphragm, but the outputs are in opposite phase. As a result, sound waves rippling out toward the sides meet at the speaker's edge and cancel. That and the relatively large size of the ElectroMotion ESL's electrostatic panel cause output at the sides to be very low relative to that of a conventional loudspeaker, which in turn minimizes side-wall reflections that tend to muddle sonic detail and stereo imaging. While the reduction in output to the sides contributes to the astonishing clarity for which electrostats are revered, the energy reflected off the wall behind the speaker opens up and deepens the sound.
Edited by Nighthawk26 - 12/9/13 at 10:58pm
post #9835 of 10203
Nighthawk - I am not an expert, but do love ML speakers (still have Prodigy's). I believe the purpose of setting them away frommthe wall is to keep the sound from rear of panel from reflecting off wall and creating a null. Spaced away from the wall diffuses the sound avoiding the null. Your acoustic treatment will absorb the rear wave, turning the ML into more of a direct radiating speaker. That's my understanding of it at least. You might want to research the outrageous theater done by the president of ML for his personal house.
post #9836 of 10203
Thanks mrevo2u... thats about as much as I've come to "understand". I use the term very varefully. What I don't know is how this translates into performance. Is it just not "idea;", will it be horrible, etc. I've called ML a few times as each time I have a different experience, and they all said it would be fine. At one point I got a guy who was snobby enough that when I questioned him, he went on to tell me his longstanding tenure at ML. I've posted in the ML thread, the dedicated HT thread, and now this one. Lots of views, yet no comments, which makes me feel like most simply don't know. We can all repeat the theory, but I need a little more.
post #9837 of 10203
I'm about to start (re)building my HT - and when I'm done will apply acoustic treatments - so I haven't read this thread yet
But wanted to ask now - Being that my walls will be 2-3 layers thick of DW+GG before I apply acoustic treatment - How do I attach the acoustic treatments to the walls - are they screwed in directly to the wall- or will there be additional thickness that I'm going to need to screw through (and should have a layer of OSB board in my wall)?

also - for when I do start the treatment - to save me from reading 328 pages of posts - is there a summary with the current consensus(es)?
post #9838 of 10203
I DIY'd a couple of panels for my lounge room. They're on my thread here:

http://www.avsforum.com/t/1454364/haydens-ht#post_23698831
post #9839 of 10203
Quote:
Originally Posted by cgott42 View Post

I'm about to start (re)building my HT - and when I'm done will apply acoustic treatments - so I haven't read this thread yet
But wanted to ask now - Being that my walls will be 2-3 layers thick of DW+GG before I apply acoustic treatment - How do I attach the acoustic treatments to the walls - are they screwed in directly to the wall- or will there be additional thickness that I'm going to need to screw through (and should have a layer of OSB board in my wall)?

also - for when I do start the treatment - to save me from reading 328 pages of posts - is there a summary with the current consensus(es)?

It would have to be severely heavy treatments if screwing into double layers dw won't hold it... Mine are quite light, I just stapled them to the dw.
post #9840 of 10203
Thx
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