Acoustical Treatments Master Thread - Page 393 - AVS Forum | Home Theater Discussions And Reviews
Forum Jump: 
 245Likes
Reply
 
Thread Tools
post #11761 of 11790 Old 03-08-2017, 09:11 PM
Senior Member
 
dchalfont's Avatar
 
Join Date: Mar 2011
Posts: 383
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 172 Post(s)
Liked: 45
I don't know if this is the sort of question to ask here, but the walls in my home theatre room vibrate loudly in certain places and I want to put about 3 screws through the wall and into the frame because when I press my hand against the vibrating places the noise stops immediately, so fixing them will obviously do the trick.

But the studs in walls are only going to be present in the places where the wall is already screwed to the frame isn't it?

Or should I be getting someone to see if the existing screws that were put through into the frame were not screwed in securely enough?

It is a brand new house. Less that 5 months since completion.

I have had a lot of problems and am taking the builder through the process to get him to fix issues with the house but I didn't raise the issue of the vibration with them because I doubt walls vibrating from $25000 equipment in a 16x16x8 room falls under expectations of construction.

But I don't want to just do whatever works, I want to do it right so that it is fixed permanenty and in a way that doesn't mess up the walls. Pulling sections of the wall out etc is also absolutely noy an option.

Basically I'm hoping I can get about 30-40 of the right type of screws put through the wall, into the frame and then filled on the ends, sanded and painted. Also a half dozen on the other side of the wall.

Is that the right track or is this a much bigger issue?
dchalfont is offline  
Sponsored Links
Advertisement
 
post #11762 of 11790 Old 03-09-2017, 02:44 AM
Advanced Member
 
Lesmor's Avatar
 
Join Date: Sep 2007
Posts: 655
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 345 Post(s)
Liked: 123
Quote:
Originally Posted by dchalfont View Post
I don't know if this is the sort of question to ask here, but the walls in my home theatre room vibrate loudly in certain places and I want to put about 3 screws through the wall and into the frame because when I press my hand against the vibrating places the noise stops immediately, so fixing them will obviously do the trick.

But the studs in walls are only going to be present in the places where the wall is already screwed to the frame isn't it?

Or should I be getting someone to see if the existing screws that were put through into the frame were not screwed in securely enough?

It is a brand new house. Less that 5 months since completion.

I have had a lot of problems and am taking the builder through the process to get him to fix issues with the house but I didn't raise the issue of the vibration with them because I doubt walls vibrating from $25000 equipment in a 16x16x8 room falls under expectations of construction.

But I don't want to just do whatever works, I want to do it right so that it is fixed permanenty and in a way that doesn't mess up the walls. Pulling sections of the wall out etc is also absolutely noy an option.

Basically I'm hoping I can get about 30-40 of the right type of screws put through the wall, into the frame and then filled on the ends, sanded and painted. Also a half dozen on the other side of the wall.

Is that the right track or is this a much bigger issue?
The 16x16x8 room dimensions might be the issue with the room modes being stimulated
Lesmor is offline  
post #11763 of 11790 Old 03-09-2017, 05:18 AM
Senior Member
 
dchalfont's Avatar
 
Join Date: Mar 2011
Posts: 383
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 172 Post(s)
Liked: 45
Quote:
Originally Posted by Lesmor View Post
The 16x16x8 room dimensions might be the issue with the room modes being stimulated
There are obviously room mpdes but that's an entirely differnt issue from vibrating walls where they are not fixed properly to the frame. Especially when the vibrations are nowhere near the corners.

I called a builder who does small jobs and asked about it, mentioning my builder and he said that he doesn't know how my builder still has a license and that he recently worked on another house built by the same a-hole who screwed up mine....and that that house had the exact same issue. Them I called the plasterer recommended by the guy I called and when I mentioned my builders name he said the same thing. He checked the house out and said that not only did he likely not use glue like he was supposed to. But that it seemed like he only used nails to fix the wall to the frame in order to cut corners and explained that a bowing in a skirting board is proof that he hasn't fixed the wall panels to the frames properly.

So it's a construction issue.

Anyway problem solution found now...
dchalfont is offline  
 
post #11764 of 11790 Old 03-09-2017, 08:31 AM
Advanced Member
 
Lesmor's Avatar
 
Join Date: Sep 2007
Posts: 655
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 345 Post(s)
Liked: 123
Quote:
Originally Posted by dchalfont View Post
There are obviously room mpdes but that's an entirely differnt issue from vibrating walls where they are not fixed properly to the frame. Especially when the vibrations are nowhere near the corners.

I called a builder who does small jobs and asked about it, mentioning my builder and he said that he doesn't know how my builder still has a license and that he recently worked on another house built by the same a-hole who screwed up mine....and that that house had the exact same issue. Them I called the plasterer recommended by the guy I called and when I mentioned my builders name he said the same thing. He checked the house out and said that not only did he likely not use glue like he was supposed to. But that it seemed like he only used nails to fix the wall to the frame in order to cut corners and explained that a bowing in a skirting board is proof that he hasn't fixed the wall panels to the frames properly.

So it's a construction issue.

Anyway problem solution found now...
That's good but if you post a question in a acoustic treatment thread don't get narked if you then get a suggestion of room modes vibrating the loose panels reply and then say of course there are room modes.
If you know that much then you also know to use another room as the one you are using is unsuitable.

I am not in the least bit interested in, as we say in the UK cowboy builders,we have enough of our own.
Lesmor is offline  
post #11765 of 11790 Old 03-09-2017, 07:15 PM
Advanced Member
 
dnoonie's Avatar
 
Join Date: Jan 2014
Location: Seattle, WA area
Posts: 924
Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 277 Post(s)
Liked: 223
Be careful, you don't want a wall to fall on you. You should check local building code. Be careful where you use screws and nails.

Building code in my area states nails must be used when building wood homes and not screws. I looked it up and the reason behind it is that screws sheer and nails bend. So in an earthquake the house built with wood and nails would be ruined but it would still hold together because and not collapse flat because the nails would bend and not break. Try a search, there are some great videos of tests out there, it's pretty interesting. In an earthquake you'd be able to crawl out of a wood house put together with nails, where a wood house built with screws would likely kill you.

Of course attaching Sheetrock is another story.

Cheers,
dnoonie is online now  
post #11766 of 11790 Old 03-10-2017, 04:28 PM
Member
 
Join Date: Nov 2016
Location: York, PA
Posts: 18
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 6 Post(s)
Liked: 1
Hi Guys! So I could use some help here. I need some help on what to do with acoustic treatments. I have a 100’ roll of 1” Linacoustic, and 8 - 2’x4’x2” panels. Where should I put them? I have an AT screen, and my theater room is 12’ wide by 20’ long. I know I want to hit the first reflection points, but my question is more of, if you had that for acoustic treatment, what would you do? Side note, I love big bass in movies, so I don’t want to reduce the bass in the room at all. Thank you.
JMAX2016 is online now  
post #11767 of 11790 Old 03-10-2017, 09:21 PM
Member
 
Join Date: Nov 2016
Location: York, PA
Posts: 18
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 6 Post(s)
Liked: 1
Just to give you guys an idea of my space. All of the fabric in the room now is acoustically transparent fabric. So I'm planning on putting the treatment behind the fabric. This is also my old screen. I now have an AT screen. the ceilings are about 8 ft high.
Attached Thumbnails
Click image for larger version

Name:	IMG_6192.jpg
Views:	59
Size:	121.1 KB
ID:	2018745   Click image for larger version

Name:	IMG_6200.jpg
Views:	53
Size:	104.1 KB
ID:	2018753  
JMAX2016 is online now  
post #11768 of 11790 Old 03-11-2017, 07:42 AM
Advanced Member
 
Livin's Avatar
 
Join Date: May 2004
Posts: 941
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 199 Post(s)
Liked: 60
Quote:
Originally Posted by erwinfrombelgium View Post
Correct, but 2x of very little is still not a lot. I mean, 150 Hz will not be absorbed much by 2" of material. It's really mid+high absorption.

This said, it's obvious that the most effective use of 2" panels is indeed with a 2" gap.
Quote:
Originally Posted by JWL.GIK View Post
Agreed. Adding an airgap roughly the same thickness as the panel itself will generally get you about another octave of useful absorption on the low end.
I ended up going with 1x4 wood.. which is really 3.5" deep. So, I'll have about a 1.5" air gap between the drywall and the OC703.

Question: Does drilling 1" holes in the wood frames really do much, like this guy did...
Attached Thumbnails
Click image for larger version

Name:	panel_1.jpg
Views:	71
Size:	102.2 KB
ID:	2019465  

________
Ltek

setup: Kodi, Paradigm-Velodyne-SVS, 120" DIY Spandex Screen, Sony 45ES
Livin is offline  
post #11769 of 11790 Old 03-11-2017, 08:37 AM
AVS Forum Special Member
 
Join Date: Sep 2015
Location: Europe, Croatia
Posts: 1,179
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 694 Post(s)
Liked: 362
Hey guys, not sure if this question was asked here. What would be preferred room finish material for a small dedicated HT room to achieve best acoustical performance? Drywall, wood paneling, something else? Of course, plan is to put acoustic treatments on top of that.

Revel Ultima Salon 2, Revel M106, Revel C208, Yamaha P5000S, Denon X5200, Panasonic 65" VT50, SVS PC13-Ultra
Kef LS50, Parasound New Classic, Focusrite 2i2
donktard is offline  
post #11770 of 11790 Old 03-11-2017, 09:26 AM
Senior Member
 
Nick V's Avatar
 
Join Date: Mar 2003
Location: Edmonton, Alberta, Canada
Posts: 295
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 51 Post(s)
Liked: 47
Quote:
Originally Posted by donktard View Post
Hey guys, not sure if this question was asked here. What would be preferred room finish material for a small dedicated HT room to achieve best acoustical performance? Drywall, wood paneling, something else? Of course, plan is to put acoustic treatments on top of that.
This stuff looks pretty good!!
QuietRock 545
donktard likes this.

Theater: Vizio 70" P-Series 4K Display/KEF LS50 L+R/Mirage BPS 400 Sub/Anthem MRX-300/Wyred4Sound STP-SE/Blue Circle BC 24/Outlaw 2200/Oppo BDP-83/Sound Application CF-X/GIK Acoustics Panels
Living Room: Vizio 55" M-Series 4K HDR Display/GoldenEar 3D Array X Front L+C+R/Rythmik L-12 Sub/Denon AVR-X3200/Oppo DVD-A/SACD Player/Outlaw OAW4
Nick V is online now  
post #11771 of 11790 Old 03-11-2017, 09:29 AM
AVS Forum Special Member
 
erwinfrombelgium's Avatar
 
Join Date: Jan 2007
Location: Flanders, Belgium
Posts: 1,175
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 438 Post(s)
Liked: 234
Drywall is most cost effective. It has the right "limp mass " properties. Best practice is double layer with GreenGlue in between. This absorbs down to 250 Hz. Sub 100 Hz is difficult to contain other than with concrete.

Building a 9.3.4 HT: DIYSG Titan LX [LCR] • Cinema 10 Max [6 Surrounds] • Beta 10CX custom [TF+TR] • LLT Mal-x 18" subs [2] • XPR-5 • MM8003 [8ch] • XMC-1 [RMC-1 wanted] • PT AT6000E • 130" Seymour Center XD • Oppo 103EU • WTB: 1 extra Mal-x 18" SW
erwinfrombelgium is offline  
post #11772 of 11790 Old 03-11-2017, 09:31 AM
Advanced Member
 
12B4A's Avatar
 
Join Date: Mar 2014
Location: CR Iowa
Posts: 502
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 308 Post(s)
Liked: 175
Quote:
Originally Posted by Livin View Post
Question: Does drilling 1" holes in the wood frames really do much, like this guy did...
It makes the frame lighter.

If I mashed the buttons correctly, 1" would seem to help with absorbing ~7khz on up for all sound hitting the panel mostly tangentially?

Life is Lambertian
12B4A is offline  
post #11773 of 11790 Old 03-11-2017, 12:55 PM
AVS Forum Special Member
 
Join Date: Sep 2015
Location: Europe, Croatia
Posts: 1,179
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 694 Post(s)
Liked: 362
Quote:
Originally Posted by erwinfrombelgium View Post
Drywall is most cost effective. It has the right "limp mass " properties. Best practice is double layer with GreenGlue in between. This absorbs down to 250 Hz. Sub 100 Hz is difficult to contain other than with concrete.
I was not asking specifically to contain sound, I have a pretty good idea what is required for that. I was wondering if any material is beneficial specifically for room acoustics, basically, to take the load off any additional acoustic treatment I might add. For example, bathroom tile or glass walls sound like a bad idea.

Revel Ultima Salon 2, Revel M106, Revel C208, Yamaha P5000S, Denon X5200, Panasonic 65" VT50, SVS PC13-Ultra
Kef LS50, Parasound New Classic, Focusrite 2i2
donktard is offline  
post #11774 of 11790 Old 03-12-2017, 03:00 AM
Member
 
Join Date: Nov 2016
Location: York, PA
Posts: 18
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 6 Post(s)
Liked: 1
From what I have read, the best practice for behind the screen wall is 1" linacoustic, poly, then 1" linacoustic. Does it matter what mm the poly is? I think BIG has said 4mm and I've heard a couple say 6mm. And does this include the side wall that goes out until the screen as well(for me it's about 36")?
JMAX2016 is online now  
post #11775 of 11790 Old 03-12-2017, 03:03 AM
AVS Forum Special Member
 
Mashie Saldana's Avatar
 
Join Date: Dec 2008
Location: UK
Posts: 1,166
Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 564 Post(s)
Liked: 357
Quote:
Originally Posted by JMAX2016 View Post
From what I have read, the best practice for behind the screen wall is 1" linacoustic, poly, then 1" linacoustic. Does it matter what mm the poly is? I think BIG has said 4mm and I've heard a couple say 6mm. And does this include the side wall that goes out until the screen as well(for me it's about 36")?
Don't confuse mm for mil (which is a thousand of a mm), the poly they are referring to is 0.004 to 0.006mm.

My HT build: Tower Cinema - 9.1.6 in a 12'x12' room

Marantz | NAD | Monitor Audio | SVS | Pioneer
Mashie Saldana is offline  
post #11776 of 11790 Old 03-12-2017, 09:23 AM
Advanced Member
 
Livin's Avatar
 
Join Date: May 2004
Posts: 941
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 199 Post(s)
Liked: 60
Quote:
Originally Posted by JMAX2016 View Post
From what I have read, the best practice for behind the screen wall is 1" linacoustic, poly, then 1" linacoustic. Does it matter what mm the poly is? I think BIG has said 4mm and I've heard a couple say 6mm. And does this include the side wall that goes out until the screen as well(for me it's about 36")?

Originally Posted by BIGmouthinDC
Per both Toole and Erskine. Fiberglass insulation in front corners for the purposes of bass trapping is waste of money. At the front corners standing waves are at their highest pressure level but lowest velocity. Fiberglass is a velocity bass absorber. You want to make a dent on bass you need membrane absorbers. Of course you should know what frequencies you need to tame because membrane traps are effective over certain frequencies. So what to do? Put a layer of 3mil plastic between the two layers of linacoustic on the front wall and it will behave as a membrane trap of sorts.

http://www.homedepot.com/p/Husky-100...083C/202184059

________
Ltek

setup: Kodi, Paradigm-Velodyne-SVS, 120" DIY Spandex Screen, Sony 45ES
Livin is offline  
post #11777 of 11790 Old 03-12-2017, 12:55 PM
Member
 
Join Date: Nov 2016
Location: York, PA
Posts: 18
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 6 Post(s)
Liked: 1
Quote:
Originally Posted by Mashie Saldana View Post
Don't confuse mm for mil (which is a thousand of a mm), the poly they are referring to is 0.004 to 0.006mm.
Okay, thank you. I actually thought it was mm.
JMAX2016 is online now  
post #11778 of 11790 Old 03-12-2017, 12:58 PM
Member
 
Join Date: Nov 2016
Location: York, PA
Posts: 18
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 6 Post(s)
Liked: 1
Quote:
Originally Posted by Livin View Post
Originally Posted by BIGmouthinDC
Per both Toole and Erskine. Fiberglass insulation in front corners for the purposes of bass trapping is waste of money. At the front corners standing waves are at their highest pressure level but lowest velocity. Fiberglass is a velocity bass absorber. You want to make a dent on bass you need membrane absorbers. Of course you should know what frequencies you need to tame because membrane traps are effective over certain frequencies. So what to do? Put a layer of 3mil plastic between the two layers of linacoustic on the front wall and it will behave as a membrane trap of sorts.

http://www.homedepot.com/p/Husky-100...083C/202184059
Okay, thanks. I'm going to go get some 3 mil today and put it up.
JMAX2016 is online now  
post #11779 of 11790 Old 03-12-2017, 01:03 PM
Member
 
Join Date: Nov 2016
Location: York, PA
Posts: 18
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 6 Post(s)
Liked: 1
Guys, can someone give me some advice on what to do on the theater side of the AT screen. I've read hundreds of pages and listened to 2 podcasts on acoustics. The problem is that they seem to conflict with each other. What Anthony Gramani says makes sense. But then I see these $300,000 theaters, and they are doing something slightly different. Mainly the percentage he says to cover. I know I want atleast 2" panels. I have all rock wool panels as of now. And I'll have what is left of my Linacoustic roll I could use.
JMAX2016 is online now  
post #11780 of 11790 Old 03-12-2017, 01:06 PM
Member
 
Join Date: Nov 2016
Location: York, PA
Posts: 18
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 6 Post(s)
Liked: 1
I could even make more panels. I just want to do it the RIGHT way!
JMAX2016 is online now  
post #11781 of 11790 Old 03-12-2017, 01:18 PM
AVS Forum Special Member
 
drunkpenguin's Avatar
 
Join Date: Jun 2004
Location: New Mexico
Posts: 4,062
Mentioned: 8 Post(s)
Tagged: 0 Thread(s)
Quoted: 1265 Post(s)
Liked: 1243
FWIW, I went from floor to ceiling panels to no panels on the front wall after reading accoustics on realtraps.com and I improved my sound big time. I have some foam panels directly behind the speakers to tame the voice echos, but I love the way my theater sounds now.
rboster likes this.

Just 'cause you're right doesn't mean I'm wrong
drunkpenguin is offline  
post #11782 of 11790 Old 03-12-2017, 04:01 PM
Newbie
 
thedrmike's Avatar
 
Join Date: Jan 2009
Posts: 14
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 5 Post(s)
Liked: 11
I would like some advice. My local building supply store has Supress Sound Deadening Board, and I'm wondering if I can use it as a substitute for Linacoustic/Insul-shield etc.

http://www.supressproducts.com/sound...ing-Board.html

Thanks!
thedrmike is offline  
post #11783 of 11790 Old 03-12-2017, 04:25 PM
AVS Forum Special Member
 
Mashie Saldana's Avatar
 
Join Date: Dec 2008
Location: UK
Posts: 1,166
Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 564 Post(s)
Liked: 357
Quote:
Originally Posted by Livin View Post
Originally Posted by BIGmouthinDC
Per both Toole and Erskine. Fiberglass insulation in front corners for the purposes of bass trapping is waste of money. At the front corners standing waves are at their highest pressure level but lowest velocity. Fiberglass is a velocity bass absorber. You want to make a dent on bass you need membrane absorbers. Of course you should know what frequencies you need to tame because membrane traps are effective over certain frequencies. So what to do? Put a layer of 3mil plastic between the two layers of linacoustic on the front wall and it will behave as a membrane trap of sorts.

http://www.homedepot.com/p/Husky-100...083C/202184059
Considering limp mass absorbers target a very narrow frequency range, which frequency can you hope to target with this sandwich?

Now looking at the DIY limp mass absorbers they build over at Gearslutz I can't imagine 3mil of plastic will do anything at all considering they use a thousand times thicker steel plates as membranes.

My HT build: Tower Cinema - 9.1.6 in a 12'x12' room

Marantz | NAD | Monitor Audio | SVS | Pioneer
Mashie Saldana is offline  
post #11784 of 11790 Old 03-12-2017, 05:02 PM
Member
 
Join Date: Nov 2016
Location: York, PA
Posts: 18
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 6 Post(s)
Liked: 1
Quote:
Originally Posted by drunkpenguin View Post
FWIW, I went from floor to ceiling panels to no panels on the front wall after reading accoustics on realtraps.com and I improved my sound big time. I have some foam panels directly behind the speakers to tame the voice echos, but I love the way my theater sounds now.
That's similar to what Anthony Gramani says. So that's what makes it confusing. I just finished installing the 1" lin, 3 mil, 1" lin. About to calibrate then start listening. If BIG says this is the way to go though, I believe him. He seems to be knowledgable as can be with this.
JMAX2016 is online now  
post #11785 of 11790 Old 03-19-2017, 11:38 PM
Advanced Member
 
dnoonie's Avatar
 
Join Date: Jan 2014
Location: Seattle, WA area
Posts: 924
Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 277 Post(s)
Liked: 223
Quote:
Originally Posted by JMAX2016 View Post
That's similar to what Anthony Gramani says. So that's what makes it confusing. I just finished installing the 1" lin, 3 mil, 1" lin. About to calibrate then start listening. If BIG says this is the way to go though, I believe him. He seems to be knowledgable as can be with this.
Check this article,http://realtraps.com/art_front-wall.htm

And this thread, https://www.gearslutz.com/board/bass...-monitors.html

Cheers,
dnoonie is online now  
post #11786 of 11790 Old Today, 12:23 PM
Member
 
Join Date: Nov 2016
Posts: 170
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 147 Post(s)
Liked: 22
Hey guys,
Hope I can get some help here. I have a 23Lx14Wx8H room. Been reading on acoustic treatment. As of now, I have 703 2" and 703 4" panels in the room. Room is specifically used for Home Theater and has a 7.2.4 system. I recently watched Anthony Grimani HT Geek video
which made me realize that my room is way off from what he was discussing.

In short, he has a 20% absorption and 25% diffusion rule. He also mentinoed that the front wall shouldn't be completely covered. Well, in my case, all I have is absorption and absorption and absorption. I have the whole front wall covered with linacoustic and all room corners have 8" 703. Then back wall is also mostly treated with absorption of 2" 703". Side wall I left the first reflection and covered 2nd reflection. Also ceiling has 4 panels of 4" 703 around 1st and 2nd reflection.

This all absorption is now making me think that the room might be absorbing way more than it needs to. I do use REW and very familiar with its usage. Now the questions

1 - Do you guys agree that a dedicated HT room with 11 channels should be 20% absorption and 25% diffusion?
2 - If yes then how much of a distance is required to use diffusion? Armani recommended to use 3D diffuser on back of MLP and 2D on Front are of MLP. My MLP is 5 feet away from back wall. Can I still use 3D diffuser. As for front, my projector screen is 10' away from MLP. Attaching the image he used in presentation. Image shows a good distance from back wall but not so much from side. So I'm guessing that 3D diffuser doesn't have to be too far.
3 - Front wall: should it not be covered with linacoustic to make it all dead?

I'm hoping that someone will jump on this post cause all this info and stuff is driving me crazy. I purchase good speakers (JBL 4722n) but now feeling that I'm not utilizing their power.

Attached Thumbnails
Click image for larger version

Name:	diffusion and absorption.PNG
Views:	66
Size:	781.6 KB
ID:	2044873  
harrisu is offline  
post #11787 of 11790 Old Today, 01:45 PM
AVS Forum Addicted Member
 
sdurani's Avatar
 
Join Date: Oct 2001
Location: Monterey Park, CA
Posts: 24,768
Mentioned: 77 Post(s)
Tagged: 0 Thread(s)
Quoted: 4593 Post(s)
Liked: 3008
Quote:
Originally Posted by harrisu View Post
In short, he has a 20% absorption and 25% diffusion rule.
That's his approach, based on his preference.
Quote:
Do you guys agree that a dedicated HT room with 11 channels should be 20% absorption and 25% diffusion?
Only if you like the resulting sound.
JonasHansen likes this.

Sanjay
sdurani is offline  
post #11788 of 11790 Old Today, 02:36 PM
Member
 
Join Date: Aug 2014
Posts: 99
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 46 Post(s)
Liked: 38
Quote:
Originally Posted by harrisu View Post
1 - Do you guys agree that a dedicated HT room with 11 channels should be 20% absorption and 25% diffusion?
2 - If yes then how much of a distance is required to use diffusion? Armani recommended to use 3D diffuser on back of MLP and 2D on Front are of MLP. My MLP is 5 feet away from back wall. Can I still use 3D diffuser. As for front, my projector screen is 10' away from MLP. Attaching the image he used in presentation. Image shows a good distance from back wall but not so much from side. So I'm guessing that 3D diffuser doesn't have to be too far.
3 - Front wall: should it not be covered with linacoustic to make it all dead?
1. 25% diffusion is waaaay too much to me, and 20% absorption is too low. From everything I've read lately and the small amount of testing I'm able to do, 40% absorption is a better rule of thumb. Diffusion is very hard to say, because the results you get vary drastically depending on the room and the MLP position. If you have 6 feet between the MLP and the diffusor, then I think you can go as high as 20% diffusion if you really want to, but if you don't have that much room to work with, you want to go with all absorption, but leave a little reflection in the room to keep the soundstage large. Diffusion in small rooms just smears everything together since the diffusor doesn't have enough space to diffuse sound into.

2. Like I said, 6 feet is bare minimum. A guy at metal-fi is playing with geofusors now and is having a weird time with them, he's finding that they work well below ear level in his room but he's still playing with them. https://www.metal-fi.com/forum/viewt...t=633&start=70

3. Don't cover the entire front wall. A lot of guys do it and say it sounds great but end up tearing most of it out after a while. A guy just did this in this thread a few pages back I think and reported that his sound opened back up substantially. It's fine to treat directly behind the speakers and in the corners behind the speakers, but any more than that is really unnecessary and costly. If you hunt around real traps you can find some articles by Ethan Winer that talk about this exact concept.

Video: Benq HT2150ST Projector --> Silver Ticket 100" Fixed Screen
5.2 Audio: PS4/Nvidia Shield --> Emotiva XMC-1 --> Emotiva XPA-5 --> Ascend Acoustics Sierra Towers/Horizon Center with RAAL tweeters (L/C/R), HTM 200 SE (surrounds), Dual Rythmik F12 subs
sludgeogre is offline  
post #11789 of 11790 Old Today, 02:54 PM
Member
 
Join Date: Nov 2016
Posts: 170
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 147 Post(s)
Liked: 22
Quote:
Originally Posted by sdurani View Post
That's his approach, based on his preference. Only if you like the resulting sound.
Yeah but this means that I have to buy all these and then install and then try and if I don't like it, I'm left with a lot of stuff. I'm sure there are some rules/theories that majority agrees upon to start with? Like, may be a way to use REW to know how dead my room is???? I don't know how to interpret RT60 but I think it is supposed to show how alive room is. Don't know if its applicable to room of my size because someone mentioned that the graph is useful only for large rooms.

Quote:
Originally Posted by sludgeogre View Post
1. 25% diffusion is waaaay too much to me, and 20% absorption is too low. From everything I've read lately and the small amount of testing I'm able to do, 40% absorption is a better rule of thumb. Diffusion is very hard to say, because the results you get vary drastically depending on the room and the MLP position. If you have 6 feet between the MLP and the diffusor, then I think you can go as high as 20% diffusion if you really want to, but if you don't have that much room to work with, you want to go with all absorption, but leave a little reflection in the room to keep the soundstage large. Diffusion in small rooms just smears everything together since the diffusor doesn't have enough space to diffuse sound into.

2. Like I said, 6 feet is bare minimum. A guy at metal-fi is playing with geofusors now and is having a weird time with them, he's finding that they work well below ear level in his room but he's still playing with them. https://www.metal-fi.com/forum/viewt...t=633&start=70

3. Don't cover the entire front wall. A lot of guys do it and say it sounds great but end up tearing most of it out after a while. A guy just did this in this thread a few pages back I think and reported that his sound opened back up substantially. It's fine to treat directly behind the speakers and in the corners behind the speakers, but any more than that is really unnecessary and costly. If you hunt around real traps you can find some articles by Ethan Winer that talk about this exact concept.
Yeah I wouldn't want the smear the sound. Before I made all the changes, I removed everything from room and when I played some music, it did sound better when I didn't have anything (no absorbtion) on back wall corners. If I put the absorption panel there, it does feel like it was absorbing more than I needed to.
I think first, I'll remove the Linacoustic from front wall cause its just absorbing everything and then try out.
One of my concern is that I feel like I don't have absorption in balance. Front wall is completely dead, back wall is 100% starting from ear level and going 4 feet up, side wall has one one panel on each side on 2nd reflection and I have 4 panels on top. The reason I didn't install more panels on side wall is because many owners of my speaker (JBL 4722n) said that it sounds great when first reflection is not absorbed. So I left that open by just having one panel on 2nd reflection. But you can see that my room is unbalanced where at one place too much absorption and one place almost nothing.
harrisu is offline  
post #11790 of 11790 Old Today, 09:42 PM
Member
 
Join Date: Nov 2016
Location: York, PA
Posts: 18
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 6 Post(s)
Liked: 1
Quote:
Originally Posted by harrisu View Post
Yeah but this means that I have to buy all these and then install and then try and if I don't like it, I'm left with a lot of stuff. I'm sure there are some rules/theories that majority agrees upon to start with? Like, may be a way to use REW to know how dead my room is???? I don't know how to interpret RT60 but I think it is supposed to show how alive room is. Don't know if its applicable to room of my size because someone mentioned that the graph is useful only for large rooms.



Yeah I wouldn't want the smear the sound. Before I made all the changes, I removed everything from room and when I played some music, it did sound better when I didn't have anything (no absorbtion) on back wall corners. If I put the absorption panel there, it does feel like it was absorbing more than I needed to.
I think first, I'll remove the Linacoustic from front wall cause its just absorbing everything and then try out.
One of my concern is that I feel like I don't have absorption in balance. Front wall is completely dead, back wall is 100% starting from ear level and going 4 feet up, side wall has one one panel on each side on 2nd reflection and I have 4 panels on top. The reason I didn't install more panels on side wall is because many owners of my speaker (JBL 4722n) said that it sounds great when first reflection is not absorbed. So I left that open by just having one panel on 2nd reflection. But you can see that my room is unbalanced where at one place too much absorption and one place almost nothing.
Harrisu,
So I've really been playing around with acoustic treatment over the past two months, moving them, stacking them (for lower freq absorption), and a loooot of listening. I have a 7.2.4 setup, with a 120" AT screen. Here's what I've learned, and maybe this will help in some kind of way.

1. Only absorb the whole front wall if you have an AT screen. Otherwise, I don't like the sound. I use 1" lin, plastic membrane, 1" lin (Thanks BIG!). I love the sound of this, because less SBIR (speaker boundary effect), great speaker localization, and great bass trapping.

2. Make sure both side walls have equal amount of absorption, and at the same height and distance. In other words, symmetrical. Otherwise, I can hear the difference. My side walls are covered about 40%.

3. I like the back wall about 50% covered with absorption. I hear this difference in the dialogue.

4. I use 3" rock wool at first reflection points, and 2" almost everywhere else.

5. Ceiling clouds, I have not tried, but I want to try the at the first reflection point on ceiling.

6. With the amount of absorption I just mentioned, the amount of power you need to reach the same SPL is greater. Meaning that if you'd regularly play movies at 60% of the receiver/amp capability, you'll need to run it at 75%. But that sound will be way more clean and linear.

7. I have not used REW yet. I have the app, but no mic. I would love to measure my room. Decay times, etc. But to my ears, this is the best my room has sounded.

What do you guys think?
JMAX2016 is online now  
Sponsored Links
Advertisement
 
Reply Dedicated Theater Design & Construction

Tags
Fv15hp Subwoofer , Denon , Audyssey

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page


Forum Jump: 

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off