# Pics of room - where to start with acoustics



## cburbs (Mar 27, 2007)

I am looking at the DIY Route but not sure where to start. I would like to start off with say Owens Corning 703 - 2 inch case of 6. So where would you place 6 panels to start off with.....?


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## bpape (Sep 14, 2006)

With just 6 pieces, you're going to make some compromises. It's not enough to do any kind of bottom end control so it will be mostly for reflection purposes.

You need to hit the side wall reflection points - most likely one panel will be on the door on the right and one opposite it. I'd also take down the poster directly opposite the equipment rack as you'll get nasty slap and pinging in that little area off to the right side.

I'd likely use the rest to do as much of the front wall as you can. You want the front wall basically totally dead. 

Next thing to consider is making some smaller chunk style triangular absorbers floor to ceiling in the front corners to help with overall bass control and SBIR control since the speakers are basically right in the corners.

Bryan


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## adogand6kids (Jul 29, 2006)

Chad,

In response to your question about where to place 6 panels, I will give you two different answers. The answers differ based on what your primary desire is for your acoustic treatment.

Option One: Absorbing First Reflections
If this is your primary desire, then place 1 panel each on the left and right side walls at the first reflection points (you may need to move some posters). To know the correct location, follow the instructions given here: http://www.realtraps.com/rfz.htm . Next, place 1 panel each behind your left and right main speakers (or you could place 2 panels on the theater's rear wall). Finally, place two panels on the ceiling to absorb first reflections there. 

Option Two: Bass Trapping 
If your main desire is to absorb low frequencies then use your panels to make corner bass traps. I am guessing that your ceiling height is just under 7 feet. Use 3 panels in each to stradel your front corners from floor to ceiling. Double up the panels to make them 4 inches thick. Let me add a suggestion that you consider buying more panels and making more than just two traps if you do want to bass trap your room. Ideally, you would place traps in the two front corners, the front corner next to your built in equipment rack, the rear corner where the standing lamp is currently located and maybe along the wall/ceiling corner under the sofitt.

Six panels is not enough to do both, and looking at your room, I am not sure it would be enough to effectivley bass trap your room. I would suggest that if you can only go with 6 panels, you use them to absorb first reflections. Then, as soon as you are able, start getting more panels and add bass traps. There are a ton of examples of DIY absorbers and bass traps on the home audio acoustics page at this forum. Look there for ideas. Hope this helps.


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## cburbs (Mar 27, 2007)

So for corner bass traps is it better to use chuncks than to just put a panel in - http://forum.studiotips.com/viewtopic.php?t=535 similiar to this.

Since I don't have tons of room in the corner would it still pay off up front?

Would I benefit by putting say a 4" thick acoustic panel on the door that leads into the room. Look at the 1st pic - brown door?

I like the look of the Dave%20Corner%20brdband%20absorber-studio.jpg


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## cburbs (Mar 27, 2007)

This looks like some good info as well - http://www.runet.edu/~shelm/acoustics/bass-traps.html


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## bpape (Sep 14, 2006)

I'd make the chunks - but at half the size since you don't have much space to the sides of the screen. That will let you get 16 triangles that are 12x12x17 out of each piece. 16 pcs at 2" thick each gives you a 32" high solid chunk from each 2'x4'x2" piece.

I'd agree that another box of 6 is in order to do the room properly.

Bryan


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## cburbs (Mar 27, 2007)

Brian,

Is it best to go from floor to ceiling? 

12*12*17 is too wide for me up front. If I do say 8" does it even pay? 

Is it possible to go smaller?


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## adogand6kids (Jul 29, 2006)

_So for corner bass traps is it better to use chuncks than to just put a panel in _
The chunks will give you absorption to a lower frequency (I couldn't tell you how low). The panels take less fiberglass and are a bit less work. So, the answer depends on how much money and time you have to invest.

_Since I don't have tons of room in the corner would it still pay off up front?_

I think I know what you are asking here - and Yes, corner traps up front behind your mains will help. You may need to move your mains forward into the room a bit.

_Would I benefit by putting say a 4" thick acoustic panel on the door that leads into the room. Look at the 1st pic - brown door?_

Do you want that 4" acoustic panel to be a bass trap? If so then the answer is no - it won't be a very effective bass trap. Do you want that 4" panel to absorb sound coming from the front speakers so it doesn't bounce back - then the answer is yes, but you don't need the panel to be 4" thick. You would do better to use 2 panels each 2" thick.


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## bpape (Sep 14, 2006)

Do what you can. Anything is better than nothing. If you only have 8", then I'd likely make the best use I can and make an 8" x 6" rectangular absorber floor to ceiling. You might also consdier building some false soffiting around the upper perimeter of the room where possible. Again, even if it's only say 6"x6", that's better than nothing. You just don't have a lot of space left over for broadband treatment.

Bryan


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## cburbs (Mar 27, 2007)

So is the 703 that much better to buy over the other two listed here?
http://www.atsacoustics.com/cat--Fiberglass-and-Mineral-Wool-Batts-and-Boards--106.html

I should be able to actually start on this finally - Again it will be started off doing 6 panels. So any suggestions added to the above would be great.


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## bpape (Sep 14, 2006)

The 60 density is OK if you're going to chunk it up for bass absorbers. I just don't care to work with it as it's a PITA to cut. It can be very effective acoustically though.

Bryan


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## cburbs (Mar 27, 2007)

Bryan - I will be building some panels for my first round - 
So here is my idea - please let me know your thoughts.
Front wall behind speaker - One panel behind the front two speakers. So this is really one panel cut in half since I only have like 11" from screen to corner.

Two panels at First reflection point - front right door and straight across from there.

This leaves 3 panels left - where would you suggest to put them?


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## bpape (Sep 14, 2006)

Ideally, you'd cover the entire front wall - thicker in corners.

I'd then start thinking about some thicker panels centered on the rear wall to catch nulls coming off there and opposite the screen.

Bryan


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## cburbs (Mar 27, 2007)

So something like this -


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## bpape (Sep 14, 2006)

That'd work.

Bryan


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## cburbs (Mar 27, 2007)

How do you figure out how high to hang them? Like say the 3 on the back wall ?
The ones behind the front speakers?


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## bpape (Sep 14, 2006)

Get the top of the panel about 6' off the floor. The idea is to get a bit up high but primarily cover behind seated head height.

Bryan


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## cburbs (Mar 27, 2007)

What about behind the front speakers and first reflection points - how high on these?


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## bpape (Sep 14, 2006)

Side reflections about the same. Behind the speakers depends on the situation - play with it a little and see what works best for you. Just sit them on some books or a milk crate or chair to change heights and see.

Bryan


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## cburbs (Mar 27, 2007)

In the corners what is the big difference if you do wedges floor to ceiling or make a panel floor to ceiling? Yes I know the wedges will be denser.


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## bpape (Sep 14, 2006)

Wedges won't necessarily be denser if made from the same materail. What they will be is thicker which puts more of a wave in the absorbtion longer and gets closer to the 1/4 wavelength optimum on lower (longer) frequencies. In essence, they'll just reach down deeper more effectively.

By the time you get enough material to do a 6" thick panel straddling, you can make a chunk style absorber of the same width and height that will reach deeper and take up less space in the room. The panel would have it's rear face hitting the walls at the same distance that the front of the wedge would be.

Bryan


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## cburbs (Mar 27, 2007)

Ok that makes sense - So you are saying this is the better way to go - 
http://www.hometheatershack.com/forums/home-audio-acoustics/7758-corner-traps-finally-finished.html


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## bpape (Sep 14, 2006)

Yes. That will take the same amount of acoustical core as a 6" thick panel straddling the corner with air behind it.

Bryan


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## cburbs (Mar 27, 2007)

Ok so locally I can get the 2" JM814 or they have a 2" Mineral Wool that is density of 8 pounds per cubic foot. Since the MW is at a good price is there any issue with using it?


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## bpape (Sep 14, 2006)

It'll be just fine for the corner absorbers.

Bryan


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## cburbs (Mar 27, 2007)

Will 8# MW work for the Panels since this is what I am starting with - This is my plan for the front.
Panel left/right of screen and one below behind center channel & left/right as 1st reflection points.


back will be like pic attatched.


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## bpape (Sep 14, 2006)

If you're DIY'ing, do teh entire front wall. 8lb will be fine for this and the back wall. For the sides, I'd personally prefer something less dense since you're going to have some reflections with pretty shallow angles of incidence dnt the denser material can allow it to skip off sometimes.

Bryan


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## cburbs (Mar 27, 2007)

For the front walls by the two main speakers - is a acoustic panel behind each speaker better or my other thought for now is make two panels and stack them on top of each other and angle them in the corner.

On the building process is there a better way to build them - one without a backing and one with.

http://swbg1.tripod.com/diy_acoustic_panels.htm

http://www.angelfire.com/sports/RCcars/acoustic_panels.htm


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## bpape (Sep 14, 2006)

How much room do you have on either side of the screen to the side walls?

Bryan


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## cburbs (Mar 27, 2007)

It is exactly 11 1/2" from the outside of my screen to the side walls. So if I made panels the MW would be 9" wide if I used 3/4" wide wood as this gives me 1/2" of space on each side of the panel - similiar to the diagram of the front wall above. I cut out a piece of cardboard that was 10 1/2" wide by 4' tall. Now if I use a acoustic panel on the front wall and my speaker has a high port and low port on the back side do I want to lower the panel as low as the lowest port on that speaker?


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## cburbs (Mar 27, 2007)

What type of fabric do most people use if they buy locally? Burlap 
Is there anything else that is usable?

With the wood frame what is the best size/type of wood to use?


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## thewire (Jun 28, 2007)

cburbs said:


> What type of fabric do most people use if they buy locally? Burlap
> Is there anything else that is usable?
> 
> With the wood frame what is the best size/type of wood to use?


I used burlap for my corner bass traps not counting the GIK ones stacked over those in the front of my room to cover the front wall. If your considering the burlap because it is cheaper or more convieninet to find, I don't think that you would regret using it. My side relection panels are also burlap. If it is appearance is very critical GOM might be the route you would like to go. The weave is slightly different also. Burlap up close looks almost like it is covered in lint. :heehee: Fortunitly mine are in a very dark room and they are black (dark color also works) and nobody would be able to tell. You want to use strong wood that is light and easy to work with. For the wood, maybe someone would comment on the different variations in the different price ranges but it is not set in stone what is best.


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## bpape (Sep 14, 2006)

You can also use Muslin. It's inexpensive, dyable, and relatively smooth in relation to burlap.

Bryan


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## Guest (May 1, 2008)

Here is a link some examples of muslin. http://tinyurl.com/3nrqu3


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## cburbs (Mar 27, 2007)

Ref Post #28 for two different style builds - is there a preference on how to build the back area of the panels?


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## cburbs (Mar 27, 2007)

Here are some shots of my first panel


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## Guest (May 12, 2008)

Looks great. Where did you get that fabric?


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## cburbs (Mar 27, 2007)

Just some cheaper fabric I found at JoAnne Fabrics. $3.99 a yard though I did get some of it on sale. I didn't buy it all at once as I wasn't sure on how it was going to stretch over the wood.

It says Black Scroll 3680899


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## chas (Jan 28, 2007)

Looks great Chad....


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## bpape (Sep 14, 2006)

I like that Fabric. Do you remember what it's called by any chance?

Bryan


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## cburbs (Mar 27, 2007)

I can look at my receipt. I basically looked over in a section where they had items seperated by colors and looked at the black cloth with designs on it. I didn't want anything too busy that showed it and this is but it doesn't show it like the rest of them. Some had skulls, circles but where big and stood out - more black on white.


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## cburbs (Mar 27, 2007)

Ok so I think I am going to change one in the back on the left...any thoughts


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## Prof. (Oct 20, 2006)

I prefer the first way you showed it..keeping all the panels vertical..


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## salvasol (Oct 31, 2006)

Prof. said:


> I prefer the first way you showed it..keeping all the panels vertical..


I agree with the Prof. ... if you want to rotate it because you want to cover more of the wall, you can make another to fit in the space you have left :dontknow:


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## cburbs (Mar 27, 2007)

Right now I only have 5 big panels so if I don't rotate it do I put it where the poster was or dead center on that back wall.


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## salvasol (Oct 31, 2006)

cburbs said:


> Right now I only have 5 big panels so if I don't rotate it do I put it where the poster was or dead center on that back wall.


I'll say dead center ... :yes:

Later when you build the other you can move it. :bigsmile:


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