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I can share picks of how I did all the acoustic stuff if you wish...just let me know.

I would love to see any pics. The hex part of my room is the back, two Berk's on a platform in the center of it. I would have to totally rebuild to put the screen back there, and I think losing that extra 5 feet would make th room to small for my 123" screen.

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As for the windows, I will go out on a limb and say that the more complete your light control is, the better it will be for the video part of the theater.

There are five total windows, double wide on the side walls, and singles on each of the "hex" walls, all completley light controlled. Black fabric covered panels that fit fit snugly into the window frames. It's wired for curtains, but I like the look of the panels and they work great.


Light control is "perfect" right now, as a flat black room, you are blind in the room if the lights are out and the projector isn't on.
 

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You'd place bass traps in the corner sections as usual.

Either corner in front would be tough to do anything. Looking at the screen the left side is the entry. The door is about 2 ft back from the screen edge. The other side is the audio cabinet doors.
 

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Quote:
Originally Posted by Caspyr /forum/post/0


Light control is "perfect" right now, as a flat black room, you are blind in the room if the lights are out and the projector isn't on.

I'd say you've got that taken care of.
 

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Quote:
Originally Posted by Ethan Winer /forum/post/0


Caspyr,


> Either corner in front would be tough to do anything.
 

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Quote:
Originally Posted by pepar /forum/post/0


I *think* he was referring to "corner" as in "Go sit in the corner." Gravity being what it it, it tends to limit the number of corners one can actually sit in.

Huh? Here's what I read:


"You'd place bass traps in the corner sections as usual."


"Either corner in front would be tough to do anything."


What did you read?
 

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Quote:
Originally Posted by Ethan Winer /forum/post/0


Huh? Here's what I read:


"You'd place bass traps in the corner sections as usual."


"Either corner in front would be tough to do anything."


What did you read?

HEY, look over there!
 

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What I am trying to say is that at the left of the screen, there is no corner. Currently about 2' behind the sceen on the left side is a curtain that is the entrance. The left side wall heads straight down past the screen, then a curtain, then the hallway to the rec room/bar area.


Plus, I was thinking of "corners" being where walls meet. I was not thinking top corner/bottom corner where the walls meet ceiling/floor. I am a 1k brain, to me a room has 4 corners not 8



That's why I need places like this, gotta love the amount of information you can get from all you guys. Thanks !!
 

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In the spirit of giving back something to this great thread, here are construction details for my absorbers (ideas borrowed from here and Bob Golds).


I chose to go with an open frame construction for reasons of (a) light weight, (b) open sides for greater total area of fiberglass exposed, & (c) ease of custom-tailoring thickness. For room aesthetics reasons, total thickness was limited to 3. I used a stack of three 1 sheets of 3 pfc rigid fiberglass in each frame. However, the construction method would also easily allow 2 of fiberglass with a 1 gap to wall (or any other desired combination). While the third sheet might not increase acoustic absorption much, it apparently does no harm and only adds a relatively small incremental cost ($3.52).



Top and bottom frames constructed from 3/4*1/2 hemlock and clamped square. Top frame used shoe moulding and mitred corners to provide a rounded front edge. Bottom frame used rectangular molding and butted corner joints.



Nailing and gluing the top and bottom frames together. Pillars are 2 1/8 for 3 1/8 total thickness.



Drilled guide holes for the #17 * 1 wire nails used to tack the mitred top frame pieces onto 3/4" square pillars using a cut-off #18 * 1 nail (an old trick my dad taught me
).



Front views of finished raw frame (left) and completed, covered, frame (right).



Speaker cloth stretched and stapled onto frame following instructions here. Cloth is actually a lot darker than it appears in this photograph. Yellow stuff is the "rigid fiberglass" acoustic absorber.



BOM (per absorber):

- 4' * 2' * 1 Johns Manville 3 pfc rigid fiberglass sheets. Source: E J Bartells, 700 Powell Ave SW, Renton, WA. 425-228-8807. Cost: 3 sheets @ $3.52 = $10.56.

- 3/4 * 1/2 hemlock 1/4 rounded shoe for front frame. Source: Lowes. Cost: 2 8' lengths at $3.36 each = $6.72.

- 3/4 * 1/2 hemlock rectangle (for back frame and 6 mid posts). Source: Lowes. Cost: 2 8' lengths at $3.36 each = $6.72.

- 3/4 * 3/4 hemlock square (for pillars). Source Dunlumber. Cost 2' @ 85 c/foot = $1.70.

- 60 wide black speaker cloth. Source Jo-Ann. Cost: 1 yd @ $6.80/yd = $6.80.

- miscellaneous (nails, glue, sandpaper, etc) $0.50.


Total cost per absorber = $33. This includes some waste as could only buy the molding in 8' lengths.


Total time per absorber (once in production mode & not counting time for glue to dry !) approx 2 - 3 hrs. So, I probably spent less time making them than reading about how to make them plus the multiple trips to various stores buy materials
.



Observations & tips:


- Top and bottom frames were laid out on a sheet of 3/4 MDF to provide a nice flat surface as the glue set. Didn't have any significant problems with warping.


- I mitred the top frames and made them out of shoe moulding to provide a nice rounded appearance. The rounding was hard to actually notice once the black grill cloth was on the frame. Despite this, and the fact that this approach requires twice as many cuts, I still think it was worth the extra effort.


- All cuts were made by hand using a 16 point dovetail saw and mitre box. All lengths were marked using pre-cut wood pieces rather than a tape measure. This really helped speed & consistency.


- Added 1/4 clearance for fiberglass so that total outside dimensions were 49 3/4 * 25 3/4 * 3 1/8.


- Didn't bother painting the wood. The bare frames and the (yellow) fiberglass are not visible through the speaker cloth.


- I was pleased with the way the finished absorbers turns out. Not too obvious that they are DIY. The 3/4" * 1/2" hemlock provided a nice balance between rigidity and weight (although something a bit beefier would be required for frames any larger than these).



Hope the above is useful to other would-be DIY'ers and thanks to other contributors to this thread


Brent
 

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Wow Brent, looks terrific. I think the rounded edges are a great touch. I only have 2 questions:


1) How are you planning on mounting them to the wall?


2) Did your rigid foam have a paper backing like 703 does? If so, what did you do with it?
 

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Felgar - Thanks for the comments. I guess the edges could also be rounded with a router. Problem is, I don't own one.


This is a works in progress so mounting has not yet been determined
. First thought is to just hang them over a couple of nails that are 5/8" proud of the wall. Nails would fit in gap between upper horizontal cross piece and fiberglass. The heads of the nails would provide a lip to help stop them falling off. However, these things are fairly light (or more accurately, have a high surface area to weight ratio) so I am not all that concerned about what would happen if they fell of the wall. Would be more of a "thud" than a "crash". The alterative would be to make little flat plate hangers, or perhaps use a short length of chain (anything that is an inch or so long and has a couple of holes) that could be screwed into both the frame and wall.


I am yet undecided if I am going to put some sort of cloth backing on the these. Once on the wall, the fiberglass cannot fall out. And the fibers seem fairly well bonded......


The rigid fiberglass I used was "unfaced". 703 is for sure available unfaced as well.


Brent
 

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I am just starting planning after months of reading. I have a room 22x22x10. (I know square is not good). Do I need to build 2x4 walls with GG and two layers of sheetrock or will the 12" cement walls keep sound from traveling. This room is under a garage with an 10" slab. Only one entry door and three sides totally underground and one side into the rest of the house. Was thinking I could just put strapping on walls and not sheetrock? Will this work or do I need to frame walls? Thanks
 

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I am on going to buy 1" Linacoustic to line the lower half of my side and front walls. I finally found it locally. I will have some left over. Can I make panels out of this (stuffing it into frames), instead of buying rigid fiberglas panels (which I am having a heck of a time finding locally)? Just trying to save cost, and to use what I have. Also, how is everyone dealing with with outlets once you mount and cover the Linacoustic? Cut holes in Linacoustic and cloth cover, and then extend the outlets 1" from the drywall? With speaker wires, RCA outs, and electric outlets, I'm not sure it will look right (e.g., nice and flat). Any thoughts on how to deal with this issue?
 

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Let me start by saying that it is a little intimidating entering a thread where some of the participants are clearly experts in their field, and are willing to go to great lengths in the pursuit of perfection. I've been plowing through this thread a little at a time over the last couple of months while in the planning stages for the re-do of my basement, and would like to get your opinions on getting the maybe 85-90% of perfection that I think should be realistically and easily achievable in my circumstance.


I'm dealing with a typical tri-level basement, not very large with ceilings that are about 7'6" when finished. This will be a VERY mixed use room - more than a dedicated home theater. In fact, I will probably do more (casual to serious) music listening than movie watching. I'm building a bar at one end and shoe-horning in a 7' pool table next to that. There will be a number of compromises as a result of everything we are attempting to do, but my goal is to achieve the best acoustic response I can, with the greatest range of usability for the room.


This room had been "finished" by the former owner of the house, and I first had to undo pretty much everything they did. So far I've torn down the sheetrock (which never had the seams taped,) reframed most of the walls (which had stud spacing anywhere from 12" to 20" on center as the mood struck,) and redone the electrical (which could have burned down the house.)


At the end of this post is my hand drawn sketch of the room. Sorry, but I haven't had time to work on this project more than 1 1/2 days a week on average, and I didn't want to spend a couple of days trying to figure out how to use SketchUp.


I'm going to put R-13 behind the drywall and in the ceiling, and was going to put 2" OC 703 behind the stage area. OC 703 superchunks in all four corners (above and below the two rear corner speakers.) I know that putting the rear surrounds in the corners is not optimum, but windows, the pool table, and other space considerations make that compromise necessary. Ditto for the side surrounds.


Finally, my thought was to cover the bottom 40 or so of the right side wall and rear wall with fabric we have picked out that is fairly heavy and passes about 50% of the acoustically transparent breath test. Behind the fabric would be 2 OC 703 for a padded wall effect. On the left side of the room there is almost no available space for doing the padded wall thing.


I was thinking that using 2 703 on the side and rear wall instead of the 1 that seems to be more the norm on these forums would make up for the lack of 703 on the left wall. In the end I decided to ask for informed directions before I got too carried away with my assumptions.


Thanks in advance for all the time and information you all share with these groups. Immediately after this post I'll post a panoramic picture of this space as it looked last week, taken from the bottom left corner of the sketch.
 

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Here is a panoramic shot of the carnage so far. This picture was shot

from the back corner of the bar (lower left-hand corner in the diagram.)

That big empty space on the left side will be a 90 gallon saltwater reef tank someday.


The wall studs are not really crooked, that and some "ghostly" tools are from the stitching program I use.

A seven foot (bar size) pool table will be going to the right of the

bar, and a curved leather sectional sofa will be in front of the Plasma, angled slightly towards the upper right-hand corner of the room.


Don't laugh, you should have seen this room a week ago!

 

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Quote:
Originally Posted by texas teacher /forum/post/0

Ya'll seem pretty detailed. What's wrong with a little Quietrock sheetrock on the walls and Quietwood on the floors? Seems a lot simpler.

These products are used for sound isolation -- to make your room quiter, and allow less sound to escape to other rooms. They do not improve in-room acoustics, as do absorber panels and other sound treatments. You need both. Sorry that it is even more complicated.



Oh, and for sound isolation, you can't just do one part of a room, because sound will happily travel right through the areas you haven't done. So a "little Quietrock sheetrock" becomes "a lot" -- enough for all your wall surfaces and ceiling.


Regards,

Terry
 

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I've put up some pics and diagrams of my project and have several questions about Positioning Acoustic Panels in an Apartment. I could really use some of the brainpower in this thread. Thanks in advance.


Please comment in this thread:
http://www.avsforum.com/avs-vb/showthread.php?t=734181
 

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Quote:
Originally Posted by patrickjherbert /forum/post/0


Let me start by saying that it is a little intimidating entering a thread where some of the participants are clearly experts in their field, and are willing to go to great lengths in the pursuit of perfection.

Sometimes I think the thread ought to be unstickied. Many views expressed at the beginning by some of the "experts" have probably evolved considerably. The use of absorption for one is over rated in this thread. (And absorption that defies room symmetry has thankfully never been highly rated.)


Firstly, one is no way NEAR perfection in terms of acoustics if the loudspeaker being used is shoddy. Clearly enthusiasts ought to be demanding better but the infatuation with loudspeakers featuring primitive easily saturated passive crossovers continues. There are indeed very few consumer loudspeakers with the requisite on and off axis flat frequency response.


Once you start with a superb loudspeaker, it's better to optimize reflection and diffusion in the horizontal plane. Early reflections can aid musicality and speech intelligibility. Diffusion affords an enveloping passive surround that complements active surround of multichannel setups. Screw the linacoustic. Any absorption, reflection or diffusion ought to be as broad in bandwidth as possible lest it unbalance the off axis prowess of the loudspeaker being used. Whereas reflections may work laterally, the front and rear reflections are best attenuated or diffused (the latter preferred with adequate distance from diffusor -quadratic residue or prime root- to listening seat). Bass distortion is the worst offender in typical rooms and the ceiling/or wall ceiling corners is a strategic choice for broadband bass traps. The rest of the ceiling can be interspersed with broadband diffusion and absorption. Tortuous calculation of reverberation times is hogwash. With a treated ceiling and furniture, one may already have enough absorption to get away with hardwood floors and area rugs. The Welti/Toole configuration of multiple subs and parametric eq of peaks below 300 Hz should round out amelioration of bass distortion not fixed by broadband bass traps and drywall flex.


Most of this is a far cry from the linacoustic loving advice you'll find in this thread. Balance out whatever advice you typically would get here with what Richard Bird, Russ Berger, John Storyk, or Floyd Toole would advocate (even though they're not always right). Google away.

Tumara Baap
 
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