# Help with Panel Placement / Options



## YW84U (Apr 29, 2007)

Good Evening All,

I'm in the throes of treating the first reflection points in my theatre build. I've done the 'mirror' technique to give me a rough idea of placement, and have marked off the areas with tape for now - covering all seating areas spread over two sofas with one on a riser. My Paradigm Monitor 7's are in my proscenium mounted a little above ear level, and very close to the wall boundaries. I've treated both sides of the speaker with mineral wool as well....

Pictures for reference:



















forgive my Photoshop, but the red lines depict the 'centres' of the drivers, and the green tape depicts the boundaries of where you can see the speakers from the seating.


The dilemma:

The area nearest the speaker appears as though it should be covered with a panel that would rest right up against the fabric for the proscenium......Acoustically good, aesthetically maybe 'not so much' :doh:

How much wiggle room would I have to move the panel back an inch or two to at least give a visual 'break' between two very large black fabric surfaces? I'm afraid that an inch or three might defeat some of the purpose behind my acoustical adventures.....

Along the same lines, I would also prefer to hang the panels portrait versus landscape - not a problem for the middle portion, but the rear seating has quite a spread - nearly four feet. I could maybe get away with two foot wide panels for the first two, but I would be leaving about 2 inches either side of the taped off boundaries untreated.....the rear part might end up two 2 ft wide panels butted together.....and....um....oh, **** I don't know :dontknow: The other kicker is, that my seating is not centred in the room, leaving the panels to go in a different places over on the right hand side:










So now I'm really scratching my head trying to come up with an idea that will treat all the right places, have at least some aesthetic value, and be somewhat symmetrical from left to right.....

Any ideas? I'm open!!

My panel plans thus far are to use vertical OC703 1" 2x4 panels (I actually found some!!) framed, beveled, and wrapped in fabric. The room is 12.5x20x8.

A shot of the rear for reference










I will also be making panels for the ceiling, but I'm not too concerned since they will be black on black and barely noticeable anyways 

One last worry - is any additional benefit to going with 2" vs 1" 703?

Thanks to all in advance!!


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## bpape (Sep 14, 2006)

There is a benefit from 2" as it will reach deeper - like down into the vocal range.

For the fronts, you can probably skip a couple inches and hit the reflection AFTER it hits the wall and catches the side of the panel. 

Lay the room and the reflections out in something like Visio (don't forget the center channel reflections - looks like you did). You may find that an alternating pattern of 24" and 12 or 18" panels will do the best job.

Bryan


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## YW84U (Apr 29, 2007)

bpape said:


> (don't forget the center channel reflections - looks like you did). You may find that an alternating pattern of 24" and 12 or 18" panels will do the best job.
> 
> Bryan


What a prompt response! Thank You ever so much Bryan - and yes, I did forget the center on the sidewalls (but not the ceiling, thank goodness).........good thing for me that there's a set of fresh eyes to tap into :whew:

Thinking about it now, with a 2" deep panel, the side of the frame facing the speaker may offer enough deflection to accommodate a few inches gap away from the proscenium - a much better solution, thanks!

With the 24/12/18 numbers you refer to, just so I understand, do you mean 24" wide panels spaced 12 or 18 apart from one another, running the length of the wall back to the seats? So, even if there ends up being 'bare wall' in the areas I've marked out, I won't be way off track? Can they all be 2x4, and symmetrical (roughly) with one another on opposite walls?

TIA!


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## Sonnie (Apr 11, 2006)

Very nice room Tom... :T


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## YW84U (Apr 29, 2007)

Thanks Sonnie! It's been a long haul, but definitely worth it..... I promise to fire up a construction thread over on the dedicated side when I get a chance!


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## Sonnie (Apr 11, 2006)

Thanks... we'll look forward to it.


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## eugovector (Sep 4, 2006)

Don't forget the ceiling.


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## bpape (Sep 14, 2006)

What I was referring to was to alternate 24" and 12" panels for some visual interest and still get good coverage. It may be better to do 24" and 18" or 18" and 12" alternating. Spacing between can be a few inches depending on the needs. 

I've seen rooms where they start with a 12, then an 18, then a 24, then back down to 18 and 12. Lots of options to get the spots covered you need and make it interesting looking. Also remember though that while there are points, it's also an area coverage thing.

Bryan


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## YW84U (Apr 29, 2007)

Ahh, makes sense now! I think I will play with Sketchup for a bit and visually test drive some various panel sizes first before I fire up the table saw :spend: Interior design isn't really my forte!

Now without measuring, is there an approximate 'rule of thumb' or guideline for amount of coverage? I know I've seen posts about over-absorbing and making rooms possibly too 'dead', but is there perhaps a formula or 'industry rule' that could indicate an approximate square foot coverage percentage?

I can measure to a degree (REW+SPL), but have yet to afford ETF or a mic/phantom power supply to realistically analyze anything over 200hz. If there's some way I can at least approximate good coverage for now and then tweak later, that would be great.


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## YW84U (Apr 29, 2007)

Okay, I think I've got it - 7 panels for each wall, using 2" OC703 2x4 wrapped in Dazian Cloth (matching the stage) in the following:


















Seems to cover all the first reflections thus far, using a combo of 24", 18" and 12" wide panels.
Different view:










Has anyone any input or feedback on aesthetics / function? I'm open! :scratchhead:



Thanks in Advance,


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## bpape (Sep 14, 2006)

Sure - that's one way to do it. All depends on the look you want and how much surface area the room can handle. Can you maybe:

In the middle, in place of the 2 24" panels, use a 12", a 24", then a 12"? Just trying to get it to not be quite so blocky.

Also, the panel way up front... Any chance of doing that floor to ceiling or at least centered vertically the same as the others (just longer)? It just looks kind of out of place up there. 

Bryan


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## YW84U (Apr 29, 2007)

Thank You Bryan - I'll play with sketchup some more this evening and try out the 12/24 idea. I agree that as it stands, the panels do come off a little 'blocky', hence my quest for constructive feedback :bigsmile:

On the other front, I anguished over the front panel and what to do.....after some sleep, I have this idea to propose - what about turning my Monitor 7's upside down? Due to the limited space I gave myself (and to pulling the trigger on those speakers instead of the discontinued Phantoms), the 7's ended up with the tweeters quite a distance above ear height. At the time, I just ran with it, dismissing the excess height as "Oh well, the tweeters are closer in height to the center channel and maybe that will help them 'blend'!!??!!"

<roll back time>










</roll back time>

If I flipped them upside down and removed the grilles, they should sit flat on the platform, and the drivers would the sit lower overall - more towards ear height, with the added bonus of allowing me to drop the front panel lower on the wall to maybe line up with their counterparts.

Could this be a good thing?


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## bpape (Sep 14, 2006)

Oh yeah - that's a problem the way it sits right now. You really want the acoustic center of the speaker between 1/3 and 1/2 of the way up the screen from the bottom (between ear height and screen center). 

Bryan


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## YW84U (Apr 29, 2007)

P.S. - is there any harm done by increasing the gap between the panels a little? Perhaps to break them up a bit more visually? Or do I risk sacrificing their benefit for the reflections?

Geez, looking at it now, maybe covering the walls with GOM and linacoustic would've been simpler!!! :bigsmile:


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## salvasol (Oct 31, 2006)

YW84U said:


> ...Geez, looking at it now, maybe covering the walls with GOM and linacoustic would've been simpler!!! :bigsmile:


What about using carpet on half the wall and panels on the top??? ... like me :bigsmile::bigsmile::bigsmile:

I don't know about my room response yet ... but to me sounds :yay::yay:


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## YW84U (Apr 29, 2007)

salvasol said:


> What about using carpet on half the wall and panels on the top??? ... like me :bigsmile::bigsmile::bigsmile:


Hi salvasol - nice room (and we share the same kids' VHS Disney collection!!)! Carpet isn't an option for me, as I prefer tweaking the acoustics with materials that have known qualities (absorption, fire ratings etc). With carpet, I wouldn't know what the performance would look like, since there are so many variables between styles. As well, I'm not 100% sure that carpet is fire-rated for wall applications, as they test it flat on the ground for flame propagation, off-gases and such. Me being paranoid and Mr. Safety, I prefer to go with rated materials just for that extra 'piece of mind'. The fabric I'm using is rated NFPA 701 Small Scale, and the 703 will be similar to rockwool's fire characteristics. Nothing's perfect mind you, but every little bit helps!

Maybe down the road, I might fabric the entire wall assemblies with fabric / linacoustic and such, but for the time being that is not in my budget :spend:

On a secondary note, I did invert my mains, which dropped my drivers pretty much down to ear level (1/2 way up the screen). Brief listening seems to show a better sound stage (real or perceived? Hahaha!).

I will redo my reflection measurement to accommodate the new positions, and start over figuring out panel combinations. Stay tuned!


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## bpape (Sep 14, 2006)

As long as you cover the reflection area, a bit more space is fine. With hard sided panels, you'll get some bounce off the wall and off the panel side back to the front so that's just as good (almost).

I'd not recommend carpet on the walls. We already have enough high frequency only absorbtion on the floor without adding more to the equation and still not dealing with the rest of the spectrum.

Bryan


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## salvasol (Oct 31, 2006)

> ... Carpet isn't an option for me, as I prefer tweaking the acoustics with materials that have known qualities (absorption, fire ratings etc). With carpet, I wouldn't know what the performance would look like, since there are so many variables between styles. As well, I'm not 100% sure that carpet is fire-rated for wall applications ...


Thank you for the compliments ...:T

The carpet I have is not the same that is used on the floors ... here is a link that describes the carpet I'm using ... http://www.acousticalsolutions.com/products/fabrics/crosspoint_fabrics.asp

Here is the data sheet they have online http://www.acousticalsolutions.com/datasheets/data_crosspoint.asp

Good luck with your project ... :wave::wave:


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## YW84U (Apr 29, 2007)

salvasol said:


> The carpet I have is not the same that is used on the floors ...


Ahhh! I was originally thinking you meant carpet-carpet......:doh:my bad..

Now I see, not really so much 'carpet' as it is a fabric designated for wall application (fire rating) with an acoustical twist! I checked out the specs, and from first blush it absorbs - but falls a bit short of what I'm looking for in regards to broadband absorption that reaches down to the vocal ranges.

* Product 125 250 500 1000 2000 4000 NRC*
Crosspoint .04 .07 .16 .28 .39 .44 .20
OC703 2" .17 .86 1.14 1.07 1.02 0.98 1.00

Thanks for the info and explanation!!!


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## YW84U (Apr 29, 2007)

Okay, so here we go!

For the frames, I ripped down some 2x6 spruce - making each frame member 2' deep, 1.5 wide, and with a bevel all way around:










Taking Bryan's advice, I ended up with a 15,21, and 27" outside width series of panels, that will end up stepping from smaller to large back to small once again. It appears I had good coverage without putting two of the larger panels in the middle of the span.










All are wrapped in Dazian Expo cloth, and I will likely hang them tomorrow (using some home-made french cleats, and maybe a couple of brads on the bottoms for good measure).

Next dilemma - has anyone any suggestions of how to ceiling-mount panels similar to these? Two panels in the middle will be overlapping (aesthetics) and hanging by hooks, but how to you effectively flat-mount the other panels in a secure fashion?

Thanks for any input!


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## YW84U (Apr 29, 2007)

Well, panels are all hung



















and I even decided to get fancy-schmancy and make some 'clouds' to finish off the front centre



















I figure it adds a little more 'dimension' rather than black dominoes :bigsmile:, and perhaps with the area of 4" 703 overlapping it might offer me some deeper absorption!

Thanks to all who gave input on my quest :T


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## Scuba Diver (Sep 28, 2007)

YW84U said:


> Thank You Bryan - I'll play with sketchup some more this evening and try out the 12/24 idea. I agree that as it stands, the panels do come off a little 'blocky', hence my quest for constructive feedback :bigsmile:
> 
> On the other front, I anguished over the front panel and what to do.....after some sleep, I have this idea to propose - what about turning my Monitor 7's upside down? Due to the limited space I gave myself (and to pulling the trigger on those speakers instead of the discontinued Phantoms), the 7's ended up with the tweeters quite a distance above ear height. At the time, I just ran with it, dismissing the excess height as "Oh well, the tweeters are closer in height to the center channel and maybe that will help them 'blend'!!??!!"
> 
> ...


I was wondering did placing your speaker in there like that effected the sound quality. Is it a bit boomy?

Hmm. a second look at this picture and it appears the sides are open. Is that what I am seeing?


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## bpape (Sep 14, 2006)

Nicely done. I really like the 3D look of the overlapped ceiling cloud.

Bryan


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## YW84U (Apr 29, 2007)

Scuba Diver said:


> I was wondering did placing your speaker in there like that effected the sound quality. Is it a bit boomy?
> 
> Hmm. a second look at this picture and it appears the sides are open. Is that what I am seeing?


By sides, I assume you mean the sides of the proscenium? If so, they are open - covered in fabric. The entire stage structure is open-weave fabric frames on velcro, and everything is decoupled from everything else. The back and side walls are treated with mineral wool in the entire cavity as well, and the speaker fronts are flush up to the front of the structure. I haven't noticed any 'boominess', or at least not since deadening the front wall. The sub is also crammed into the corner, and the response does suffer, but I'm trying to even it out with the treatments and tweaking with my BFD. 
I know that technically its poor that the mains are crammed into the corners (less than 2ft clearance), but it was a compromise with screen area available. To the ear, all sounds good so far prior to calibration and further treatments, but I have not done any full-range testing with REW (only have an SPL right now).


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## YW84U (Apr 29, 2007)

bpape said:


> Nicely done. I really like the 3D look of the overlapped ceiling cloud.
> 
> Bryan


Thanks Bryan! Just remember you played a major role in how this all worked out :bigsmile: I'll try and post some 'better' overall pictures once I have a chance, so that members can view things easier - tough to shoot in a nearly black room!!


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