Acoustical Treatments Master Thread - Page 351 - AVS Forum
Forum Jump: 
 42Likes
Reply
 
Thread Tools
post #10501 of 10530 Old 10-26-2014, 07:01 AM
AVS Special Member
 
cgott42's Avatar
 
Join Date: Jan 2001
Location: Spring Valley, NY USA
Posts: 2,301
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 68 Post(s)
Liked: 16
How is rigid foam - like this?
I have some extra 2" boards (thinking I can glue together to make 4") and want to treat my baseboard (where floor and wall intersect) behind the front speakers (also perhaps in a ceiling/wall intersection above the speakers)
ellisr63 likes this.
cgott42 is offline  
Sponsored Links
Advertisement
 
post #10502 of 10530 Old 10-26-2014, 09:47 AM
AVS Special Member
 
ellisr63's Avatar
 
Join Date: Jul 2002
Location: Northern California, In the HT
Posts: 2,154
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 202 Post(s)
Liked: 250
Quote:
Originally Posted by archiguy View Post
What's the best way to attach the Linacoustic to the back wall (painted drywall on 2x6's at 16" O.C.)...?
I believe that some people are using screws (long), and fender washers... I have also seen some screws and washers made specifically for it but I can't remember where.

Denon 4520ci, (3) JBL 2360As/EV DHA-1s, (3) 1/4 Pie bass bins, MiniDSP 2x4s, (4) Klipsch HIPs, (2) Klipsch KP3002s, PS3, XBox 360, (3) Intel NUCs, Monoprice Redmere, Monster HTPS7000, 2 SUPER SPUD subs, Panasonic AE8000us SeymourAV 180 (195" diagonal) scope screen, Yamaha P7000s (for the subs), (2) Yamaha P2500s amps for the front (3) bass bins.
ellisr63 is offline  
post #10503 of 10530 Old 10-27-2014, 08:15 AM
Advanced Member
 
myfipie's Avatar
 
Join Date: Aug 2005
Location: Atlanta, GA
Posts: 958
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 23 Post(s)
Liked: 43
Quote:
Originally Posted by cgott42 View Post
How is rigid foam - like this?
I have some extra 2" boards (thinking I can glue together to make 4") and want to treat my baseboard (where floor and wall intersect) behind the front speakers (also perhaps in a ceiling/wall intersection above the speakers)
That sort of foam has NO acoustic value at all to it. Basically it would be waste of funds. Look for rigid fiberglass or mineral wool. If using foam then you want open celled foam and honestly don't look for it to do wonders. Most of the "real" acoustic foam is to thin or small to be all that effective.
http://www.gikacoustics.com/comparin...44-bass-traps/

Glenn Kuras
GIK Acoustics

http://www.gikacoustics.com

myfipie is offline  
post #10504 of 10530 Old 10-27-2014, 09:21 AM
Senior Member
 
Jacob B's Avatar
 
Join Date: Apr 2001
Location: DK-6000 Kolding, Denmark
Posts: 269
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 6 Post(s)
Liked: 12
Need OC703 rigid fiberglass in Europe?

If any Northern Europeans are interested in OC703, I have 5 boxes of 2" rigid fiberglass boards for sale in the classified section:

OC703 rigid fiberglass in Europe
Jacob B is online now  
post #10505 of 10530 Old 10-28-2014, 08:12 PM
Member
 
Maklar's Avatar
 
Join Date: Jul 2004
Location: House of the Mouse, FL
Posts: 151
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 22 Post(s)
Liked: 18
Quote:
Originally Posted by myfipie View Post
That sort of foam has NO acoustic value at all to it. Basically it would be waste of funds. Look for rigid fiberglass or mineral wool. If using foam then you want open celled foam and honestly don't look for it to do wonders. Most of the "real" acoustic foam is to thin or small to be all that effective.
http://www.gikacoustics.com/comparin...44-bass-traps/
Would using foam over insulation impact the effectiveness of the insulation? I want to do tufted acoustic panels and thought of using foam over the insulation to help keep the rigidity of the tufts.
Maklar is offline  
post #10506 of 10530 Old 10-30-2014, 01:28 PM
Senior Member
 
thestoneman's Avatar
 
Join Date: Apr 2008
Location: Silver Spring, MD
Posts: 249
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 72 Post(s)
Liked: 25
DIY Schroeder diffuser panels

I have access to a CNC router and I am planning DIY Schroeder panels. Does anyone have dimensions I can use so my material is deep enough and cuts are affective?

Also, any thoughts on the effectiveness using expanded PVC (Sintra) with a painted finish?

-
My Theater Build

Equipment List: Denon X5200, Epson 6030, 120" Carada cinemascope screen, Panamorph U480, Oppo-103, Emotiva XPA-5, SVS PB12-NSD, LSA Statement LCR & surround speakers, Def Tech ProCinema 1000 rears & front wides, DefTech DI5.5R Atmos overheads, Grafik Eye 3106
thestoneman is online now  
post #10507 of 10530 Old 10-30-2014, 09:29 PM
AVS Special Member
 
BasementBob's Avatar
 
Join Date: Jan 2004
Location: Oakville, Ontario, Canada
Posts: 4,726
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 44 Post(s)
Liked: 77
Quote:
Originally Posted by thestoneman View Post
DIY Schroeder panels. Does anyone have dimensions I can use so my material is deep enough and cuts are affective?
knowing there were online calculators for this out there, I googled.
This is the first one I found
http://www.subwoofer-builder.com/qrdude.htm
(There are skyline numbers elsewhere)
nickbuol likes this.

An amateur built the Ark. Titanic was built by professionals. Of course Noah took a little advice.
BasementBob is offline  
post #10508 of 10530 Old 10-31-2014, 08:41 AM
Senior Member
 
thestoneman's Avatar
 
Join Date: Apr 2008
Location: Silver Spring, MD
Posts: 249
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 72 Post(s)
Liked: 25
Quote:
Originally Posted by BasementBob View Post
knowing there were online calculators for this out there, I googled.
This is the first one I found
http://www.subwoofer-builder.com/qrdude.htm
(There are skyline numbers elsewhere)
Awesome. Thanks!

-
My Theater Build

Equipment List: Denon X5200, Epson 6030, 120" Carada cinemascope screen, Panamorph U480, Oppo-103, Emotiva XPA-5, SVS PB12-NSD, LSA Statement LCR & surround speakers, Def Tech ProCinema 1000 rears & front wides, DefTech DI5.5R Atmos overheads, Grafik Eye 3106
thestoneman is online now  
post #10509 of 10530 Old 11-03-2014, 01:05 PM
Member
 
hv9200's Avatar
 
Join Date: Feb 2006
Location: NH
Posts: 187
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 16 Post(s)
Liked: 20
Hello All,

great thread and tons of info here...really hard to read all through it so I thought I could ask a basic question.

I have received a couple of recommendations for my theater room (one open wall into larger room) from GIK and Realtraps and they both essentially recommended that I add a few bass traps to the corners of the room and line my closed wall with HF absorption panels to make up for the open side, I am looking to make some DIY panels and have poster images printed onto AT fabric. The question I have is what material differentiates the LF panels from the HF panels...is it just thickness? I am looking at the OC 703 material and am unsure if that is a bass trap of a HF absorber...

sorry if this is answered in the thread somewhere, I did a few searches and came up with just too much info to sort through.

"although he walks among us, he is not one of us"
hv9200 is offline  
post #10510 of 10530 Old 11-03-2014, 03:05 PM
Senior Member
 
Jacob B's Avatar
 
Join Date: Apr 2001
Location: DK-6000 Kolding, Denmark
Posts: 269
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 6 Post(s)
Liked: 12
If no alucraft on the OC 703, only thickness decides frequency band of the absorption. 1" = HF, 4" = broadband absorption (only little Low level bass unless panel is placed in corner).

For effective absorption below 125 Hz, you need more than 12" (or some sort of membrane in front of the fiberglass), which is why such panels normally are placed in corners.

HF only is generally not recommended - broadband is preferred.
Add an airgap behind the fiberglass if the budget cannot afford enough OC703, but space is available for a thicker panel.

Cheers,
Jacob
ellisr63 likes this.

Last edited by Jacob B; 11-03-2014 at 03:07 PM. Reason: Typo
Jacob B is online now  
post #10511 of 10530 Old 11-04-2014, 06:42 AM
Member
 
hv9200's Avatar
 
Join Date: Feb 2006
Location: NH
Posts: 187
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 16 Post(s)
Liked: 20
Quote:
Originally Posted by Jacob B View Post
If no alucraft on the OC 703, only thickness decides frequency band of the absorption. 1" = HF, 4" = broadband absorption (only little Low level bass unless panel is placed in corner).

For effective absorption below 125 Hz, you need more than 12" (or some sort of membrane in front of the fiberglass), which is why such panels normally are placed in corners.

HF only is generally not recommended - broadband is preferred.
Add an airgap behind the fiberglass if the budget cannot afford enough OC703, but space is available for a thicker panel.

Cheers,
Jacob
Thanks Jacob, just so I understand you correctly, a HF only panel would be 1" and a broadband is 4"...and even at 4" (w/o alucraft) the LF benefits are only realized if corner placed?

that being said, for my room, I should use 4" 703 for the side wall, and 4" 703 for the corners to cover both some HF and some LF corner trapping?

"although he walks among us, he is not one of us"
hv9200 is offline  
post #10512 of 10530 Old 11-04-2014, 01:47 PM
Senior Member
 
Jacob B's Avatar
 
Join Date: Apr 2001
Location: DK-6000 Kolding, Denmark
Posts: 269
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 6 Post(s)
Liked: 12
Basically, yes to all :-)
HF only is generally not recommended for small room acoustics. However, it used to be (8-10 years ago) standard treatment in home theatre for sidewalls up to ear height.
For the corners, you could also make a "super chunk" corner trap, which basically is a 4'x2' fiberglass panel cut in either 4 or 8 triangles and stacked in the corners from floor to ceiling. Front it with a small frame with AT fabric. You could use cheaper fluffy type fiberglass for the super chunks rather than the OC703. Knauf Ecose fiberglass is a good indoor environment friendly product for that. They also make more rigid, OC703 equivelant, fiberglass or mineral wool.
ellisr63 likes this.
Jacob B is online now  
post #10513 of 10530 Old 11-04-2014, 11:23 PM
Senior Member
 
asarose247's Avatar
 
Join Date: Mar 2010
Location: SoCal
Posts: 467
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 68 Post(s)
Liked: 51
Ceiling Treatments changes?
Now that ATMOS puts the speakers IN or ON the ceiling
what sort of challenges do the more experienced / knowledgeable room measurers/ treaters expect , if anything, to be addressed
I ask this as I expect to use on -ceiling speakers, aimed at the MLP, 42 inches ahead, behind and left and right of the MLP, within angle suggestions , a 7 foot square
Would a cloud of OC703 2" or 3" roxul an inch or 2 from the ceiling help in the reduction of HF or even broadband reflections off the ceiling from the outer edges or the speakers dispersion characteristics (at least the "top half") ?
could this add some clarity and clearer separation between TF's and TR's , i.e. directing more on axis sound at the MLP?, yet still allowing the ATMOS "bubble " to envelop?
you can see how this evolves to then maybe having a angled cloud over the surrounds, maybe even the rears, if you go for 7.x.4
reduced peripheral HF reflections that "lift and separate" yet allow a measureablt satisfactory unified ATMOS or DSU envelope.
I realize this is a new wrinkle/take on what is already a huge/well known/much discussed/strongly individual circumstances subject but as I contemplate the info wrt to finally selecting and AVR,
I would like to be prepared to hear insights about what the resident experts think the problems might be, how to define or recognize them and the sources and what might be done to measure the results of various treatment suggestions.
It's a lot I know but this is the place to at least ask, for a start


Thank you

Denon X4000 , Emotiva UPA7, Yamaha 663 for 14.3, configurable from 10.3 and up
Klipsch F3 FL/R, G-28 CenterLow, Icon 25 CenterHigh, RC3II: SL/R SLX: Rears ,TF & TR, RB51's:FH
2 30" BF THTLP'S and SubMaximus and Inuke6000DSP
Mitsy DLP 73837 Xbox1 PS4 Panny BD 220
asarose247 is online now  
post #10514 of 10530 Old 11-10-2014, 07:25 AM
Advanced Member
 
myfipie's Avatar
 
Join Date: Aug 2005
Location: Atlanta, GA
Posts: 958
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 23 Post(s)
Liked: 43
Quote:
Originally Posted by Maklar View Post
Would using foam over insulation impact the effectiveness of the insulation? I want to do tufted acoustic panels and thought of using foam over the insulation to help keep the rigidity of the tufts.
Hard closed foam will actually reflect so I would not recommend it.

Glenn Kuras
GIK Acoustics

http://www.gikacoustics.com

myfipie is offline  
post #10515 of 10530 Old 11-11-2014, 02:37 PM
Senior Member
 
thestoneman's Avatar
 
Join Date: Apr 2008
Location: Silver Spring, MD
Posts: 249
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 72 Post(s)
Liked: 25
Here is a SketchUp file that I can export to my CNC router. My plan is to make deflection panels out of 2" thick HDU foam with a painted finish. The square dimensions are 3" x 3".

Anyone see any issues?
Attached Thumbnails
Click image for larger version

Name:	Tile1va.jpg
Views:	52
Size:	164.8 KB
ID:	362281  

-
My Theater Build

Equipment List: Denon X5200, Epson 6030, 120" Carada cinemascope screen, Panamorph U480, Oppo-103, Emotiva XPA-5, SVS PB12-NSD, LSA Statement LCR & surround speakers, Def Tech ProCinema 1000 rears & front wides, DefTech DI5.5R Atmos overheads, Grafik Eye 3106
thestoneman is online now  
post #10516 of 10530 Old 11-11-2014, 02:56 PM
Advanced Member
 
asoofi1's Avatar
 
Join Date: Mar 2011
Location: South Riding, VA
Posts: 722
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 238 Post(s)
Liked: 128
Quote:
Originally Posted by thestoneman View Post
Here is a SketchUp file that I can export to my CNC router. My plan is to make deflection panels out of 2" thick HDU foam with a painted finish. The square dimensions are 3" x 3".

Anyone see any issues?
This makes me wish I had a CNC machine. What kind of install are you doing?

---------------------------------------------------------------
for sale/trade: Final Price Drop ~ BNIB LG OLED Curved TV 55EA9800 ~Best Black Levels Ever~ 3-yr Extended Warranty Included
ht: LCR JTR 212HT~Surr. Four JTR 8LP~Hi/Wi Four Elemental Designs Cinema 6 eD6c~Subs Two JTR Orbit Shifter LFU~AV Marantz SR7008
asoofi1 is online now  
post #10517 of 10530 Old 11-11-2014, 03:10 PM
AVS Special Member
 
HopefulFred's Avatar
 
Join Date: Mar 2007
Location: Atlanta, GA
Posts: 2,920
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 199 Post(s)
Liked: 223
Why not extend the bandwidth and improve the pattern with a proper 2D QRD?
HopefulFred is online now  
post #10518 of 10530 Old 11-11-2014, 06:23 PM
Senior Member
 
thestoneman's Avatar
 
Join Date: Apr 2008
Location: Silver Spring, MD
Posts: 249
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 72 Post(s)
Liked: 25
Quote:
Originally Posted by HopefulFred View Post
Why not extend the bandwidth and improve the pattern with a proper 2D QRD?
How much depth do I need for a good 2D diffuser? I was going to place diffusers on the ceiling in front of the screen and on the back wall.

To be honest, I just started messing with the idea of building diffusers and don't know all that much about them...including where they should be located for best effect.

-
My Theater Build

Equipment List: Denon X5200, Epson 6030, 120" Carada cinemascope screen, Panamorph U480, Oppo-103, Emotiva XPA-5, SVS PB12-NSD, LSA Statement LCR & surround speakers, Def Tech ProCinema 1000 rears & front wides, DefTech DI5.5R Atmos overheads, Grafik Eye 3106
thestoneman is online now  
post #10519 of 10530 Old 11-11-2014, 07:19 PM
AVS Special Member
 
HopefulFred's Avatar
 
Join Date: Mar 2007
Location: Atlanta, GA
Posts: 2,920
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 199 Post(s)
Liked: 223
Really, the first questions should be, "Do I need diffusion?" and "Why?" Diffusion is a good addition to most listening rooms, I'd wager. But, as you suggest, "where" is the hard part. Diffusion acts to redirect and delay reflected energy with minimal energy loss, compared to plain absorption. So, without knowing anything about the energy decay in your room we can't say with much confidence. Still, we can make some generalizations, I suppose (though I am not by any means the most qualified to do so).

Diffusion of some sort is often recommended for first reflection points on side walls and ceilings. If the room size, speaker location, and seating position lead to a very high gain set of early reflections it might be most appropriate to absorb or pursue a hybrid design that both absorbs and diffuses. Or maybe 2D diffusion reduces the gain enough to maintain the purity of the direct speaker signal (if that is what you want) by redirecting and delaying the energy's arrival at your listening position. Or you might find that 1D diffusion does a better job of letting you enjoy the wide soundstage that your speakers might create. See how there's lots of options? The choice hinges on several things: room size; speaker location; seating location; speaker dispersion/off-axis performance; content (stereo vs multi-channel music vs home theater); and last-but-perhaps-most-important - preference. (Have I confused this enough? Go back to the first sentence of this paragraph.)

The details of all those parameters (especially speaker design and location details) would suggest the bandwidth you might need for diffusion. Once that is known, you can start to compromise and fail to meet that need, most likely (nice, huh?).

The bandwidth of most diffusors is defined by the depth of the deepest wells (the difference between the tallest and shortest sections) and the width of the wells (the 3x3 you indicated in your design). In order to extend diffusion to lower frequencies the wells should be made deeper. In order to extend the high frequency limit upward, the wells should be narrower. Once those two features are defined, you need to determine the pattern that fits in your space and that you can build - it's not random.

The whole process can be a little daunting and gets pretty complex. Here's a link with some good background reading links that you maybe haven't seen: https://www.gearslutz.com/board/bass...-diffusor.html As a practical matter, it might be simplest to combine your needs and desires and basic understanding with the compromises you can identify in popular commercial products, and emulate them.
thestoneman likes this.
HopefulFred is online now  
post #10520 of 10530 Old 11-12-2014, 08:31 PM
Senior Member
 
thestoneman's Avatar
 
Join Date: Apr 2008
Location: Silver Spring, MD
Posts: 249
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 72 Post(s)
Liked: 25
My goal is not to create a perfect sounding room, but experiment with some treatments to improve the room acoustics using trial and error. I don't pretend to know the black science that is room acoustics. My hope is that messing around with diffusion and absorption treatments will net a room that sounds pleasant.

That said, sounds like increasing the cell depth is something I should be doing. HDU foam can be stacked easily to make a 3" deep material. I am trying to avoid creating a dead room, but want to help Audyessy out as much as I can.

-
My Theater Build

Equipment List: Denon X5200, Epson 6030, 120" Carada cinemascope screen, Panamorph U480, Oppo-103, Emotiva XPA-5, SVS PB12-NSD, LSA Statement LCR & surround speakers, Def Tech ProCinema 1000 rears & front wides, DefTech DI5.5R Atmos overheads, Grafik Eye 3106
thestoneman is online now  
post #10521 of 10530 Old 11-12-2014, 08:37 PM
AVS Special Member
 
HopefulFred's Avatar
 
Join Date: Mar 2007
Location: Atlanta, GA
Posts: 2,920
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 199 Post(s)
Liked: 223
Quote:
Originally Posted by thestoneman View Post
That said, sounds like increasing the cell depth is something I should be doing.
I think so.

I hope I didn't seem to be talking down to your or around you. It's hard to communicate the right tone and the right details for the audience sometimes. It might be worth you starting your own thread to discuss your plans and your results.
HopefulFred is online now  
post #10522 of 10530 Old 11-13-2014, 04:29 AM
Advanced Member
 
myfipie's Avatar
 
Join Date: Aug 2005
Location: Atlanta, GA
Posts: 958
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 23 Post(s)
Liked: 43
Fred gave you some GREAT advice.. Perhaps it might be best for you to list more info about your room, pictures and so on. It might be that diffusion really is not the answer to your room. BTW what kind of CNC router do you have?

Glenn Kuras
GIK Acoustics

http://www.gikacoustics.com

myfipie is offline  
post #10523 of 10530 Old 11-13-2014, 07:00 AM
Senior Member
 
thestoneman's Avatar
 
Join Date: Apr 2008
Location: Silver Spring, MD
Posts: 249
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 72 Post(s)
Liked: 25
Quote:
Originally Posted by myfipie View Post
Fred gave you some GREAT advice.. Perhaps it might be best for you to list more info about your room, pictures and so on. It might be that diffusion really is not the answer to your room. BTW what kind of CNC router do you have?
My company has (2) Multi-Cam machines capable of routing on 3 axes.

Here is a photo of the room (view from where the bar will be). The basics are, 14' x 35' space with one end being the screen wall and the other end will be a full/traditional built in bar area. NOTE: The riser is NOT set in place yet.

I plan to add diffuser panels on the ceiling between the MLP and the screen and absorption panels scattered/staggered on the walls.
Attached Thumbnails
Click image for larger version

Name:	IMG_2589.jpg
Views:	55
Size:	154.5 KB
ID:	365041  

-
My Theater Build

Equipment List: Denon X5200, Epson 6030, 120" Carada cinemascope screen, Panamorph U480, Oppo-103, Emotiva XPA-5, SVS PB12-NSD, LSA Statement LCR & surround speakers, Def Tech ProCinema 1000 rears & front wides, DefTech DI5.5R Atmos overheads, Grafik Eye 3106
thestoneman is online now  
post #10524 of 10530 Old 11-13-2014, 07:12 AM
Senior Member
 
thestoneman's Avatar
 
Join Date: Apr 2008
Location: Silver Spring, MD
Posts: 249
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 72 Post(s)
Liked: 25
Quote:
Originally Posted by HopefulFred View Post
I think so.

I hope I didn't seem to be talking down to your or around you. It's hard to communicate the right tone and the right details for the audience sometimes. It might be worth you starting your own thread to discuss your plans and your results.
Not at all...totally appreciate the fact that you are trying to help me. I hope I didn't come across as being unappreciative. Fact is, all I know about sound waves is that they bounce off of surfaces in varying wavelengths. I am admittedly "wingin' it" here so criticism is more than welcome!

I'll definitely consider the 3" depth...I've looked at QRD calculators and know that more depth is better. My ceiling is 7'-10.5" so I'm concerned about aesthetics, but 3" should be fine.

-
My Theater Build

Equipment List: Denon X5200, Epson 6030, 120" Carada cinemascope screen, Panamorph U480, Oppo-103, Emotiva XPA-5, SVS PB12-NSD, LSA Statement LCR & surround speakers, Def Tech ProCinema 1000 rears & front wides, DefTech DI5.5R Atmos overheads, Grafik Eye 3106
thestoneman is online now  
post #10525 of 10530 Old 11-18-2014, 07:07 AM
Senior Member
 
memmo's Avatar
 
Join Date: Jun 2012
Location: Barrie, Ontario Canada
Posts: 377
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 23 Post(s)
Liked: 21
I need to pick up some insulation to use as bass traps behind my false wall and I'm having difficulty sourcing OC703 (or any of the equivalents) locally. I can find them about an hour a way, but since I need a bunch (and have a small hatchback) it would require multiple trips. Before I do that, I've read that many folks up here in Canada have been using Roxul Comfortboard IS as it is easily available at Home Depot. I'm curious to know how it compares in density (and ultimately effectiveness) to the 703. Basically, how do I make sense of the numbers below?

Here's a link: http://www.homedepot.ca/product/roxu...exterio/995375


Here's a comparison -- using info I found from a technical data sheet I found on Roxul's site.

OC 703 (3")
125HZ - 0.53
250HZ - 1.19
500HZ - 1.21
1000HZ -1.08
2000HZ - 1.01
4000HZ - 1.04
NRC - 1.10


Roxul Comfortboard IS (3")
125HZ - 0.75
250HZ - 0.82
500HZ - 0.89
1000HZ - 0.94
2000HZ - 1.00
4000HZ - 1.00
NRC - .90

The Big Bay Home Theater Build Thread
My personal theater build on Kempenfelt Bay, Barrie Ontario Canada

Last edited by memmo; 11-18-2014 at 07:12 AM.
memmo is offline  
post #10526 of 10530 Old 11-18-2014, 03:37 PM
AVS Special Member
 
BasementBob's Avatar
 
Join Date: Jan 2004
Location: Oakville, Ontario, Canada
Posts: 4,726
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 44 Post(s)
Liked: 77
memmo:


The Roxul Comfortboard IS (3") looks fine to me, provided it doesn't have the aluminum vapor barrier or black coating stuck to one side.
Higher numbers are more absorption, with anything around 1.00 += 0.15 being as good as it gets.
The "250hz 0.82" is a tiny bit low but not much, but the "125hz 0.75" is nicer than the OC 703.
In another sense, the Roxul seems more evenly broadband which might be good, rather than the sharper dropoff in the 703 at 125hz.
The numbers are similar to RXL 60 / RXL 80 which I know is fine ( http://www.bobgolds.com/AbsorptionCoefficients.htm ).
A difference of 40% you probably won't be able to hear (i.e. 1.00 vs 0.60, not 0.01 vs 0.40 which you would hear and would be 4000%). A difference of 20% you probably won't be able to measure.

An amateur built the Ark. Titanic was built by professionals. Of course Noah took a little advice.

Last edited by BasementBob; 11-18-2014 at 03:50 PM.
BasementBob is offline  
post #10527 of 10530 Old 11-18-2014, 04:16 PM
AVS Special Member
 
BasementBob's Avatar
 
Join Date: Jan 2004
Location: Oakville, Ontario, Canada
Posts: 4,726
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 44 Post(s)
Liked: 77
Quote:
Originally Posted by memmo View Post
since I need a bunch (and have a small hatchback) it would require multiple trips.
[humor]
http://www.nairaland.com/attachments...c1e73087d17dd1
http://transportfool.com/wp-content/...overloaded.jpg
http://www.swapmeetdave.com/Humor/Workshop/Overload.htm
BasementBob is offline  
post #10528 of 10530 Old 11-19-2014, 07:08 AM
Senior Member
 
memmo's Avatar
 
Join Date: Jun 2012
Location: Barrie, Ontario Canada
Posts: 377
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 23 Post(s)
Liked: 21
Thanks for the insight

Now I have to figure out how to make the best out of the side walls where I've only accommodated for 1" behind my fabric panels. As I've come to learn this is far from ideal and using any absorption may/may not make things even worse.

That being said, There are a dozen + builds in the same predicament and the owners are happy with the rooms...

Any best practices I can try? How about some RPG BAD diffuser panel clones on the upper side walls with 1" of Linacoustic?

The Big Bay Home Theater Build Thread
My personal theater build on Kempenfelt Bay, Barrie Ontario Canada
memmo is offline  
post #10529 of 10530 Old 11-19-2014, 07:13 AM
AVS Special Member
 
HopefulFred's Avatar
 
Join Date: Mar 2007
Location: Atlanta, GA
Posts: 2,920
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 199 Post(s)
Liked: 223
Quote:
Originally Posted by memmo View Post
How about some RPG BAD diffuser panel clones on the upper side walls with 1" of Linacoustic?
I don't think I would go to the trouble of building a BAD panel unless I really wanted it at a specific reflection point. Away from early reflection points, you can't beat exposed drywall for maintaining sound energy (as far as I know), and diffusing it is of marginal utility, IMO.
HopefulFred is online now  
post #10530 of 10530 Old 11-19-2014, 07:18 AM
Senior Member
 
memmo's Avatar
 
Join Date: Jun 2012
Location: Barrie, Ontario Canada
Posts: 377
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 23 Post(s)
Liked: 21
Quote:
Originally Posted by HopefulFred View Post
I don't think I would go to the trouble of building a BAD panel unless I really wanted it at a specific reflection point. Away from early reflection points, you can't beat exposed drywall for maintaining sound energy (as far as I know), and diffusing it is of marginal utility, IMO.
Good to know. I suppose I'll just have to try a bunch of options. I have 2" of Linacoustic on the front wall (with 3mil poly in-between) and I'll have corner bass trapping behind the false wall. On the rear wall, I'm doing 3" of OC 705 with a 1" gap and will possibly entertain some more corner trapping if required.. its just the side walls that I'm limited to 1" -- so perhaps I should at very least do some 1" at the first reflection points and leave everything else exposed drywall and see what its like.

I do have a friend with a CNC, so the BAD panels would be free...

The Big Bay Home Theater Build Thread
My personal theater build on Kempenfelt Bay, Barrie Ontario Canada
memmo is offline  
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