AVS › AVS Forum › Home Entertainment & Theater Builder › Dedicated Theater Design & Construction › Acoustical Treatments Master Thread
New Posts  All Forums:Forum Nav:

Acoustical Treatments Master Thread - Page 273

post #8161 of 9546
10/29/11 at 6:01pm
Quote:
Originally Posted by fotto View Post

OK, I get it that there's no air gap in your example drawing. My question more pertains to the graph you presented above with comparison of 703 and regular insulation. I was under the impression you are making a comparison there for a corner trap....if so, then why is there an air gap of 12" included in the model?

it was to detail how differing flow-resistivity values perform - not necessarily as a corner trap (eg, a rear wall trap).

oc703



pink
Reply
Reply

AVS Top Picks

post #8162 of 9546
10/30/11 at 1:45am
robc - you are showing the biggest asset right in your photos - HUGE access to the corners within the room.

dont let any of the commentary here overwhelm you. if you're willing to put a little effort in, you'll accomplish real results. there's a fine community here, even if the recommendations may seem a little overwhelming at first.

while the thin absorption and shallow diffusers will most certainly make a 'difference' in sound in the room, the real importance is in the mid-lower specular region (where the bulk of the energy content is).

the goal is most certainly not to create a dead room with a high % of the room treated with (broadband specular) absorption. caveat that LF/bass modal absorption in small acoustical spaces - well, you can never have too much.

the fact that you are adamant and posting many follow-ups show you are at least interested in what's happening within your room. very cool. many post a simple question, become overwhelmed, and drop it. dont take the path of least resistance. there is an ultra-valuable community here that will sort you out.
Reply
Reply
post #8163 of 9546
10/30/11 at 2:09am
bookmark for later:
http://www.gearslutz.com/board/studi...er-v2-1-a.html

http://www.avsforum.com/avs-vb/showt...7#post18486257
Reply
Reply
post #8164 of 9546
10/30/11 at 2:26am
Quote:
Originally Posted by localhost127 View Post

robc - you are showing the biggest asset right in your photos - HUGE access to the corners within the room.

dont let any of the commentary here overwhelm you. if you're willing to put a little effort in, you'll accomplish real results. there's a fine community here, even if the recommendations may seem a little overwhelming at first.

while the thin absorption and shallow diffusers will most certainly make a 'difference' in sound in the room, the real importance is in the mid-lower specular region (where the bulk of the energy content is).

the goal is most certainly not to create a dead room with a high % of the room treated with (broadband specular) absorption. caveat that LF/bass modal absorption in small acoustical spaces - well, you can never have too much.

the fact that you are adamant and posting many follow-ups show you are at least interested in what's happening within your room. very cool. many post a simple question, become overwhelmed, and drop it. dont take the path of least resistance. there is an ultra-valuable community here that will sort you out.

Than k you, If we did have people here like you, pepar it wouldn't be the same....your info and attemntion to detail is very admirable and the fact that you share your info is VERY respectable. I have a saying "Knowledge is NOT power unless you share it with others and you have!
Reply
Reply
post #8165 of 9546
10/30/11 at 2:27am
Quote:
Originally Posted by localhost127 View Post

bookmark for later:
http://www.gearslutz.com/board/studi...er-v2-1-a.html

http://www.avsforum.com/avs-vb/showt...7#post18486257

Bookmarked and put in my notepad!
Reply
Reply
post #8166 of 9546
10/30/11 at 4:11am
Quote:
Originally Posted by robc1976 View Post

Than k you, If we did have people here like you, pepar it wouldn't be the same....your info and attemntion to detail is very admirable and the fact that you share your info is VERY respectable. I have a saying "Knowledge is NOT power unless you share it with others and you have!

+1. Your willingness to share detailed information over and over again is very valuable.
Much appreciated!!!
Reply
Reply
post #8167 of 9546
10/30/11 at 7:46am
Quote:
Originally Posted by orcarola25 View Post

+1. Your willingness to share detailed information over and over again is very valuable.
Much appreciated!!!

Those 2 guys and others have taught me a lot in the last couple of days....great guys!
Reply
Reply
post #8168 of 9546
11/6/11 at 10:04am
big request: i remember earlier in the year that someone posted 'plans' for the building of an elevated rear seating platform, but treating it as a bass absorber, complete with proper hole diameters and locations.
it will take me a week to find it again, which, if no one can link it to me, i will do.
just trying to save time.
thanking in advance,
walt
Reply
Reply
post #8169 of 9546
11/6/11 at 12:11pm
Quote:
Originally Posted by yacht422 View Post

big request: i remember earlier in the year that someone posted 'plans' for the building of an elevated rear seating platform, but treating it as a bass absorber, complete with proper hole diameters and locations.
it will take me a week to find it again, which, if no one can link it to me, i will do.
just trying to save time.
thanking in advance,
walt

this?

http://www.avsforum.com/avs-vb/showthread.php?t=1103345
Reply
Reply
post #8170 of 9546
11/6/11 at 12:23pm
That thread went 8 posts and then died almost 3 years ago. I'd PM the member for folloow-up info to see whether or not it made any difference and if it was worth all the work.
Reply
Reply
post #8171 of 9546
11/6/11 at 2:52pm
Let me know what you find out. I'm doing riser build in a couple weeks. I would love to get some details on how to make it into a broad band bass trap. I have roughly the same space as that thread.
Reply
Reply
post #8172 of 9546
11/7/11 at 10:25am
Quote:
Originally Posted by yacht422 View Post

big request: i remember earlier in the year that someone posted 'plans' for the building of an elevated rear seating platform, but treating it as a bass absorber, complete with proper hole diameters and locations.
it will take me a week to find it again, which, if no one can link it to me, i will do.
just trying to save time.
thanking in advance,
walt

Quote:
Originally Posted by Brad Horstkotte View Post

this?

http://www.avsforum.com/avs-vb/showthread.php?t=1103345

Look at this recent thread, 2nd page.
http://www.avsforum.com/avs-vb/showt...t=riser&page=2
Reply
Reply
post #8173 of 9546
11/7/11 at 1:19pm
Quote:
Originally Posted by yacht422 View Post

big request: i remember earlier in the year that someone posted 'plans' for the building of an elevated rear seating platform, but treating it as a bass absorber, complete with proper hole diameters and locations.
it will take me a week to find it again, which, if no one can link it to me, i will do.
just trying to save time.
thanking in advance,
walt

as i hoped, much good advice has been provided. given that i'm 70, and math was never my strong suite, the book referenced by local host will not fill my shelves (although a well thumbed 'Toole', is there). So, again my thanks, and a broadband unit seems to be the best next step.
Walt
Reply
Reply
post #8174 of 9546
11/7/11 at 2:06pm
Quote:
Originally Posted by yacht422 View Post

math was never my strong suite

Just thought I would add a reference for those of us who are not mathemagicians. Hyperphysics is a website written and maintained by one of my former professors. While he is a physicist (thus a mathemagician), his website is largely conceptual, and written so that undergraduates and even high school students can get a lot out of it. This is, of course, no guide for design and construction, but can help to fully conceptualize the major variables that work to make a Helmholtz resonator. (At least, I think so...)

http://hyperphysics.phy-astr.gsu.edu...es/cavity.html

Fred
Reply
Reply
post #8175 of 9546
11/8/11 at 12:17pm
thx for the link: as you know, there is a LOT of information there!
walt
Reply
Reply
post #8176 of 9546
11/9/11 at 11:34am
Hello!

Would anyone have suggestions on what a total newb to acoustics should first consider for treating a small dedicated theater? Is there any one thing that every dedicated room should have that would drastically improve audio to a non audiophile? I have yet to run any real tests at this point since I'm not at that stage, but my room is a bit of an odd shape with a false wall being built for an AT screen.

My plan was to worry about this after I get the guts of the theater together but I'm just wondering if I should take anything in to consideration now? My build thread has layouts to show the room dimensions if it helps. The wall behind the screen is the foundation for a bay window above, so it has two 45 degree walls and it's concrete behind the drywall. We are not worrying about soundproofing the room, it's just my wife, kid and myself but it's a long narrow room with a riser at the back and I wouldn't want sounds echoing heh.

For example, is insulating a riser a necessity?

Thanks!
Reply
Reply
post #8177 of 9546
11/9/11 at 1:17pm
Quote:
Originally Posted by localhost127 View Post

cheap, pink fluffy attic insulation (uncompressed).

gas flow resistivity value of the porous material is what's important. 34" faced superchunks of pink fluffy (or larger, if you can do it). UNCOMPRESSED. you will need horizontal supports every few feet such that the layers at the top do not compress the layers at the bottom.

Are there measurements generated and available that compare something more rigid like 703 against uncompressed fluffy pink against something like roxul safe 'n sound? For my 34" superchunks I was going to use Safe n Sound but obviously won't if fluffy is more effective. Shelving would provide a place to attach fabric as well so I'm not against it.
Reply
Reply
post #8178 of 9546
11/9/11 at 2:03pm
Quote:
Originally Posted by Felgar View Post

Are there measurements generated and available that compare something more rigid like 703 against uncompressed fluffy pink against something like roxul safe 'n sound? For my 34" superchunks I was going to use Safe n Sound but obviously won't if fluffy is more effective. Shelving would provide a place to attach fabric as well so I'm not against it.

I'm curious about this too. From what I have seen so far, all this gas flow resistivity talk is coming from the Chris Whealy program. I'm willing to give it the benefit of the doubt, but is there any real world testing that bears out the better performance of the loosely packed fluffy insulation?
Reply
Reply
post #8179 of 9546
11/9/11 at 2:35pm
This article below mentions on page 5 when discussing gas flow resistivity that low flow resistivity materials are good for high frequencies and high flow resistivity materials are better for low frequencies.

http://www.universalaet.com/en/docs/...fle-design.pdf

This seems to be verified by comparing the absorption characteristics on Bob golds website. Denser materials seem to have more absorption at lower frequencies than the less dense materials. I know it is just one article, but it does support the current standard practices.
Reply
Reply
post #8180 of 9546
11/9/11 at 2:43pm
Quote:
Originally Posted by stockmonkey2000 View Post

This article below mentions on page 5 when discussing gas flow resistivity that low flow resistivity materials are good for high frequencies and high flow resistivity materials are better for low frequencies.

http://www.universalaet.com/en/docs/...fle-design.pdf

This seems to be verified by comparing the absorption characteristics on Bob golds website. Denser materials seem to have more absorption at lower frequencies than the less dense materials. I know it is just one article, but it does support the current standard practices.

However the assertion that fluffy pink (very low flow resistivity) is best for a 34" face superchunk would basically be in direct contradiction to what you've just said. By my understanding, as depth increases, flow resistivity must decrease. So a superchunk being very deep, needs low flow resistivity. I can see that from an intuitive perspective; if flow is too resisted the sound wave will reflect off the surface rather than penetrate and be absorbed. Not sure if that's a reasonable explanation but it "seems" plausible.
Reply
Reply
post #8181 of 9546
11/9/11 at 4:23pm
figured I would post some pics of some traetments I have redone.

Here is the foam I had with all reflection points "Left side MLP"




GIK suggested 3 panels on this side and the farthest panel is not touching the "tri-trap" although it looks like it LOL!!




Here is the foam I had with all reflection points "right side MLP"



GIK suggested 3 panels on this side also.




Here is the Tr-trap in the corner, I have 2 tops coming also that will stack on these full size ones and will extend it to the top.



Here is the foam I have on the ceiling with reflection points (all 3 seats) and I have 6 242 panels on the way to put in place of the foam.



So far the bass has improved dramitaclly and the detail has also increased dramitacly over the foam.
Reply
Reply
post #8182 of 9546
11/9/11 at 4:46pm
Wow, just ... wow.
Reply
Reply
post #8183 of 9546
11/9/11 at 4:58pm
Quote:
Originally Posted by robc1976 View Post

figured I would post some pics of some traetments I have redone.

So far the bass has improved dramitaclly and the detail has also increased dramitacly over the foam.

Would you mind commenting on what the panels left/right wall are made of (material, depth etc.)?

I'll bet you'll get some additional improvement when you fill in your corner traps as well.
Reply
Reply
post #8184 of 9546
11/9/11 at 7:07pm
Quote:
Originally Posted by fotto View Post

Would you mind commenting on what the panels left/right wall are made of (material, depth etc.)?

I'll bet you'll get some additional improvement when you fill in your corner traps as well.

I think the let side of MLP as 1 to many panels but it is just to make sure.

Here they are:

http://gikacoustics.com/gik_242.html
Reply
Reply
post #8185 of 9546
11/9/11 at 7:08pm
Quote:
Originally Posted by pepar View Post

Wow, just ... wow.

There was a lot of curse words used in getting those reflection points...never realized how many there where...I was only doing 1 seat before LOL!!
Reply
Reply
post #8186 of 9546
11/9/11 at 7:13pm
You should have made a video. Timelapsed it would have been cool.

Jeff
Reply
Reply
post #8187 of 9546
11/9/11 at 7:34pm
Quote:
Originally Posted by pepar View Post

You should have made a video. Timelapsed it would have been cool.

Jeff

ROFLMAO!!! I am lucky I have a cool wife!! By the end she wanted to kill me though
Reply
Reply
post #8188 of 9546
11/10/11 at 10:51am
a point of clarification, if you please.
re: first reflections;
is there ANY advantage of having 2" rfg, followed with a 2"air gap, followed by 2" of rfg, and then either the wall or an additional air gap, TBD?
thx
walt
Reply
Reply
post #8189 of 9546
11/10/11 at 11:02am
The air gap allows the absorbing material to be located in a position where the velocity of the wavelength is higher, so the positive effect of the air gap is to relocate the material away from the wall where there is zero velocity (and therefore where no absorbtion can occur). The air itself isn't helping the absorbtion; the new position of the fiberglass is what's helping.

Therefore, instead of the alternating gap design you've proposed, your most effective use of a panel of that depth would be 4" rigid fiberglass over a 2" air gap, or even better over a 4" air gap.
Reply
Reply
post #8190 of 9546
11/10/11 at 10:13pm
excellent info thanks
Reply
Reply
New Posts  All Forums:Forum Nav:
  Return Home

AVS Top Picks

AVS › AVS Forum › Home Entertainment & Theater Builder › Dedicated Theater Design & Construction › Acoustical Treatments Master Thread