Additional room treatments for LS9's

[jmck407]

Now that I have my LS9's want to add more treatments to make the room more suited for the new speakers. Problem is I don't know much about how best to treat a room for this type of speaker, or in general for that matter. The room they are in has ATS panels, and a GIK tri-trap pair. The room dimensions are 16ft wide, 19.5 ft long, and has ceilings that are 10ft high that vault to about 15 ft between the mains and the listening positions.

When I bought the treatments (from fellow TCA user JVGillow) received suggestions on placement in an audiocircle thread. The first suggestion made was to get the 4" panels mounted on the ceiling to cover the peaks of the vault it has. Could not accomplish that, because I had no way to get up to the height required to place the panels there. Ironically, the LS9's may have solved that problem for me....the shipping crates (coffins), they came in look big enough and sturdy enough where I should be able to use them to increase the height of the ladder and get where I need to be to mount the panels at the vault's peak. Now that the room has the LS9's is the vault still one of the first things on my list, or has the change in speaker type made this unnecessary...had Mini-Strata's in there before the LS9's.

This link has pictures of the room with the panels, the LS9's in position, and a few other shots showing the front, rear and side walls, and the ceiling: http://cid-2f89f19edfb31f29.skydrive...20in%20theater. I purchased a set of four used eighth nerve adept triangles, and am thinking of using two at the front/side/ wall ceiling corners. Does it make sense to do this, given the GIK tri-traps on the floor of these corners? Also, when covering the peaks of the vault, do I need to get as close as possible to covering the entire vault (width of the room)? It would be about 4 24x48x4" panels to get the entire vault, or would getting most of it with 3 of the panels be fine?

Another question is what (if anything) to add to the front wall behind the speakers, I am somewhat limited with the screen. Currently it has two of the 24x48x4" panels there (almost directly behind the speakers)...have been thinking about adding four more to get panels all along the bottom of the screen, as much for visual reasons as any sound improvement. Want to have a uniform color/material along the bottom of the screen. With only the two panels sometimes the wall below the screen has two colors from the projector light over splash displaying on wall vs. panel. Will adding panels here give acoustic improvements, or could it actually make things worse acoustically? Also, are the 24x48x4" panels being wasted in this location, Bryan mentioned the two inch panels were fine in this location in the earlier thread, but not sure if this was because of the speaker type (Mini-strata) and what I had to work with in panels, or if 2" panels generally are o.k. behind all types of speakers (e.g. stratas vs LS9's). If 4" panels have advantages in this location, am willing to purchase them instead of 2" panels....but if there aren't any reasons for them, the 2" panels are a less expensive.

I was thinking of getting four 24x48x2" panels to cover the french doors, two more to fill in gaps at the back wall, and four to get the side walls above and below the surrounds. Overkill?? If so which if any make sense? As seen in one of the photos, have a 24x48x2" panel in the middle window, this is typically covered by the curtain....does the panel still work o.k. with a curtain covering it? Most of the time the french doors are open, that frees up two of the panels slated for the doors....good idea to put them in front of the other windows...maybe with stands...make sense?

Answers to the above questions and other treatment suggestions are greatly appreciated.

[cdy2179]

You could treat the vault but it looks like it'll be reflecting mostly back towards the front of the room....

You definately need to get a mirror and catch more 1rst reflections along the side wall from all three speakers in the front stage.

Also your back wall has panels placed more for looks than use...I'd place them so they cover the entire rear wall at ear level to help cover all three front at all seats.. You really need to get a mirror and if you see one of the front 3 treat it.
The surrounds are kinda optional as some prople like a diffused sound anyway.
Here is a pic of the panels on my rear wall.


Read up on panel building...I bought 2" panels from ATS acoustics

http://www.atsacoustics.com/item--Roxul-Acoustical-Fire-Batts-Mineral-Wool-2-inch-Case-of-6--1006.html

And built my 2'x4'x2" panels for about $18 a peice.

If you look at the specs you'll see that this material absorbs well to just under 500hz and building the panel open back and spacing off the wall 1-1/2" or so will help extend pretty good to 300hz or so...at these frequencies you'll be having more problems with peaks and nulls than hearing reflections therefore 4" are really not necesssary at all... of cousre for bass traps (corner traps and such other than wedge/chunk style) they are handy.

[jmck407]

You could treat the vault but it looks like it'll be reflecting mostly back towards the front of the room....

You definately need to get a mirror and catch more 1rst reflections along the side wall from all three speakers in the front stage.

Also your back wall has panels placed more for looks than use...I'd place them so they cover the entire rear wall at ear level to help cover all three front at all seats.. You really need to get a mirror and if you see one of the front 3 treat it.


Read up on panel building...I bought 2" panels from ATS acoustics

http://www.atsacoustics.com/item--Roxul-Acoustical-Fire-Batts-Mineral-Wool-2-inch-Case-of-6--1006.html

And built my 2'x4'x2" panels for about $18 a peice.

If you look at the specs you'll see that this material absorbs well to just under 500hz and building the panel open back and spacing off the wall 1-1/2" or so will help extend pretty good to 300hz or so...at these frequencies you'll be having more problems with peaks and nulls than hearing reflections therefore 4" are really not necesssary at all... of cousre for bass traps (corner traps and such other than wedge/chunk style) they are handy.

Thank You for the reply. You are mostly right about the back wall, at least with the smaller square panels...was not sure what to do with them. I do plan to use two or three of the 2" panels to fill in the back wall as much as possible. All the current ATS panels have backs to them, after reviewing their site, they seem to sell backless (at a price premium), and recommend using them in corners. I may just take the backs off the two 4" panels in the back corners...as long as it is not all that painful of a modification.

With respect to the ceiling vaults....they are going to be difficult to get at, and would only attempt it if the consensus is they are a major problem.

[cdy2179]

If you mount the ATS acoustic panels flat to the wall they extend great to 500hz...opening the back and shimming them out allows you to catch waves slightly lower.. it's not a must but It cost pennies as I just used peices of 2x4 to shim it out and I like the look vs flat against the wall.

I personally wouldn't waste my money buying the panels already built....they are way to easy to build yourself and you can pick out your own material and sizes...I don't know if you missed it but I spent $18 a panel for all materials..everything! They actually use the material I linked to in their already built panels.

As for that vault...by looking at the pics it'll be reflecting the mains back toward the front of the room an not at you. They aren't first reflection points and should be much of a factor and probably help if anything vs having a flat ceiling.

As for the back wall ..the gaps between panels are allowing whatever speaker your ears align with free reign to muddy your sound, If I were you I'd place 2 of the rear panel horizontally at ear level this will catch all reflections that could bounce of the rear wall and hit your ears and then maybe take the other 4' panel and place it above these two and use the smaller ones the the sides of it creating a wall of absorption. That it self will probably make a very noticable difference.

As for the sides you could use some of the corner panels to test or heck the may serve you better on the walls vs the corners but that's something you'd have to check out but 4' corner traps are probably having a very minumal effect on smoothing your bass. I'd test but I'm sure the huge difference the'd make on the walls would more than win over. Your sides are probably your biggest problem area... take your mirror and see how many places you can see your fronts....and then try the next seat...I sit 15' from my screen and 13' from my rocket 850s and probably 80% of the wall has treatments but that's what it took to properly treat the room.

I will say this after treating the room it was istantly incredicble... the room has an errie hear a pin drop sound to it now and vocal clarity is crystal clear.

If I were you I'd get a mirror and treat every 1rst reflection.. you could probably get away with 1 large panel horizontal with small ones to each side on the rear wall... similar to my back wall... this would free up two panels to be used somewhere else in the room.

As far as adding panels to the front wall... the panels would be better off served at reflection points... usually panels behind the speakers are to help with port resonance with rear ported designs which may not be much of a factor in your room but I'd treat it last personally as it's not a relection point. If you have extra panel they may help absorb a little port resonance but I'd save it for last.

If you want a cool aesthetic look for your front wall...paint it black..I did this on my front wall and ceiling and love it... it helps pull you into the movie. Click on the picture above to see the front wall and more pics of the room.

[jmck407]

If you mount the ATS acoustic panels flat to the wall they extend great to 500hz...opening the back and shimming them out allows you to catch waves slightly lower.. it's not a must but It cost pennies as I just used peices of 2x4 to shim it out and I like the look vs flat against the wall.

I personally wouldn't waste my money buying the panels already built....they are way to easy to build yourself and you can pick out your own material and sizes...I don't know if you missed it but I spent $18 a panel for all materials..everything! They actually use the material I linked to in their already built panels.

$18/panel...hmm....much better than the $50+ for the pre-built ones.I have extra burlap that JvGillow gave me when I purchased his panels. Any problems getting the fabric to snug up against the mineral wool without a back? Did you just use a staple gun, or something else?

As for that vault...by looking at the pics it'll be reflecting the mains back toward the front of the room an not at you. They aren't first reflection points and should be much of a factor and probably help if anything vs having a flat ceiling.

As for the back wall ..the gaps between panels are allowing whatever speaker your ears align with free reign to muddy your sound, If I were you I'd place 2 of the rear panel horizontally at ear level this will catch all reflections that could bounce of the rear wall and hit your ears and then maybe take the other 4' panel and place it above these two and use the smaller ones the the sides of it creating a wall of absorption. That it self will probably make a very noticable difference.

O.k. on the vault, don't have to push me on this one :). Putting the rear panels horizontal sounds like a good idea, will try it out.

As for the sides you could use some of the corner panels to test or heck the may serve you better on the walls vs the corners but that's something you'd have to check out but 4' corner traps are probably having a very minumal effect on smoothing your bass. I'd test but I'm sure the huge difference the'd make on the walls would more than win over. Your sides are probably your biggest problem area... take your mirror and see how many places you can see your fronts....and then try the next seat...I sit 15' from my screen and 13' from my rocket 850s and probably 80% of the wall has treatments but that's what it took to properly treat the room.

So the 4" have advantages over 2" panels on the sides also. Why? Just the extra size absorbs more? Thought the 4" panels were for problem bass areas, but admittedly, have only done minimal research on panels.

I will say this after treating the room it was istantly incredicble... the room has an errie hear a pin drop sound to it now and vocal clarity is crystal clear.

If I were you I'd get a mirror and treat every 1rst reflection.. you could probably get away with 1 large panel horizontal with small ones to each side on the rear wall... similar to my back wall... this would free up two panels to be used somewhere else in the room.

I noticed a big difference with the current layout versus none. Interested to see how much better I can get things, without too much time/effort.

As far as adding panels to the front wall... the panels would be better off served at reflection points... usually panels behind the speakers are to help with port resonance with rear ported designs which may not be much of a factor in your room but I'd treat it last personally as it's not a relection point. If you have extra panel they may help absorb a little port resonance but I'd save it for last.

If you want a cool aesthetic look for your front wall...paint it black..I did this on my front wall and ceiling and love it... it helps pull you into the movie. Click on the picture above to see the front wall and more pics of the room.

[cdy2179]

to see the difference between 2" and 4" look at the link below.

http://www.atsacoustics.com/page--Selecting-the-Right-Acoustic-Material--ac.html

The 4 extends better to 125hz...spacing the 2" off of the wall can get the 2" to perorm almost as well... keep in mind the average freq. of the human voice is 1000 hz... so you're absorbing well within that range... and also when you get to 200hz or so the frequencies as much less directional and the peaks and nulls caused by the room are primarily the issue and not reflections. Basically for wall panels 4" is a waste of money and for the extra tad bit of performance you get that probably coulddn't detect anyway.

Bulap:not listening: ... I'd go to the fabric store...I got mine from Wal-Mart in the $1.50 a yard section... you can get any color any print..just make sure it's breathable...blow through it (DIY trick)...hold it up to your ear and see if the sound of your spouses or whoevers voice changes... think speaker grill material but a little heavier. You can easily recover everything to match using a hot-glue gun and a cheap staple gun.

For the frames I just ripped up a sheet of 7/16" MDF into 2" strips..I used wood glue and a cheap Harbor Freight brad nailer and it went quick.... I also used a round over bit in a router on the front edge to give it a little rounded look once covered.

to hold the material in place I actually used thin paneling cut into triangles at all four corners and two 4" strips along the back from left to right.... this gave the frame support and holds the material in place( I stapled the accoustic material along the inside of the frame). I used a net like fabric on the back of the paneling just to hold any loose fibers in place. Then i wrapped it all and glue and stapled it in the back. Put a small peice of 1-1/2" blocks on each bottom corner and a 4" peice of 2x4 cut into a french cleat attatched to the top 4" brace of paneling on the back. I mounted the other half of the cleat to the wall and simply hung it like a picture....They look very proffesional.


For bass control you have to create a trap by placing panels across a corner (looks like that's what you've done in some corners) and the depth of the trap determines how low it absorbs...super chunks are the most effective. If your not sure about any of the terms just google them. Proper sub placement is still a must and much more important.

I can see by your pics that the side walls are a major problem...I'm sure you'll be floored after you get all of the points covered... but it'll take probably 4 panels on each wall between you and you speakers ...at least 2 panel (or several small ones) laid horizontally on the back wall. You may have enough in your room already!

Just so you know my panels are acually 2'x 5' so my back wall panels are 10' long with two laid horizontal and not 8'. I simply cut a 1' peice to fill in the space the 4' material left. On the other side walls i just left the top 1' without absorption material as it is way too high to be a reflection problem but I liked the look of the taller panels.

[cdy2179]

Just wanted to throw it that with the height of the LS-9s being like 6-7 feet and having tweeters from the floor up... well you'll need some tall panels as well.... sit in your seat and after find a speaker with the mirror on the wall and have your helper slide the mirror up and down to see how tall the panels need to be.

[kevinzoe]

Now that I have my LS9's want to add more treatments to make the room more suited for the new speakers. Problem is I don't know much about how best to treat a room for this type of speaker, or in general for that matter. The room they are in has ATS panels, and a GIK tri-trap pair. The room dimensions are 16ft wide, 19.5 ft long, and has ceilings that are 10ft high that vault to about 15 ft between the mains and the listening positions.

When I bought the treatments (from fellow TCA user JVGillow) received suggestions on placement in an audiocircle thread. The first suggestion made was to get the 4" panels mounted on the ceiling to cover the peaks of the vault it has. Could not accomplish that, because I had no way to get up to the height required to place the panels there. Ironically, the LS9's may have solved that problem for me....the shipping crates (coffins), they came in look big enough and sturdy enough where I should be able to use them to increase the height of the ladder and get where I need to be to mount the panels at the vault's peak. Now that the room has the LS9's is the vault still one of the first things on my list, or has the change in speaker type made this unnecessary...had Mini-Strata's in there before the LS9's.

This link has pictures of the room with the panels, the LS9's in position, and a few other shots showing the front, rear and side walls, and the ceiling: http://cid-2f89f19edfb31f29.skydrive...20in%20theater. I purchased a set of four used eighth nerve adept triangles, and am thinking of using two at the front/side/ wall ceiling corners. Does it make sense to do this, given the GIK tri-traps on the floor of these corners? Also, when covering the peaks of the vault, do I need to get as close as possible to covering the entire vault (width of the room)? It would be about 4 24x48x4" panels to get the entire vault, or would getting most of it with 3 of the panels be fine?

Another question is what (if anything) to add to the front wall behind the speakers, I am somewhat limited with the screen. Currently it has two of the 24x48x4" panels there (almost directly behind the speakers)...have been thinking about adding four more to get panels all along the bottom of the screen, as much for visual reasons as any sound improvement. Want to have a uniform color/material along the bottom of the screen. With only the two panels sometimes the wall below the screen has two colors from the projector light over splash displaying on wall vs. panel. Will adding panels here give acoustic improvements, or could it actually make things worse acoustically? Also, are the 24x48x4" panels being wasted in this location, Bryan mentioned the two inch panels were fine in this location in the earlier thread, but not sure if this was because of the speaker type (Mini-strata) and what I had to work with in panels, or if 2" panels generally are o.k. behind all types of speakers (e.g. stratas vs LS9's). If 4" panels have advantages in this location, am willing to purchase them instead of 2" panels....but if there aren't any reasons for them, the 2" panels are a less expensive.

I was thinking of getting four 24x48x2" panels to cover the french doors, two more to fill in gaps at the back wall, and four to get the side walls above and below the surrounds. Overkill?? If so which if any make sense? As seen in one of the photos, have a 24x48x2" panel in the middle window, this is typically covered by the curtain....does the panel still work o.k. with a curtain covering it? Most of the time the french doors are open, that frees up two of the panels slated for the doors....good idea to put them in front of the other windows...maybe with stands...make sense?

Answers to the above questions and other treatment suggestions are greatly appreciated.

Hi,
I'd highly recommend you read Dr Floyd Toole's latest book before you do anthing further. If you aren't familiar with the name, he'd dedicated his working life to acoustical research and his book will educate you on what kind of treatment goes where and why. A must read.

In a nutshell, he recommends 6" thick absorption panels (anything thinner acts as a low-pass filter and skews the reflections' frequency spectrum to throw off the speaker's sound you paid dearly for) in the middle of the front and back walls to attenuate damaging reflections coming from coming from the same direction as the speakers. With the natural absorption of people, furnishings, broadloom/rugs, you should opt for diffusion on the side walls and ceiling and bass traps in all four room corners (floor-to-ceiling) and likely in the ceiling/wall corner behind your couch. One dimensional diffusion that scatters sound horizontally is best for side walls from the seating position forward towards the front wall. Two dimensional diffusion on either side of the back wall absorption in the centre of the wall will help add a sense of listener envelopment - a positive thing.

I too have GIK products, including the Tri-Traps bass traps and I can tell you from first hand experience that you'll need many more than two of them. While each one adds more control over bass nodes each by themselves is not very effective. For example, I have 8 Tri-Traps in a single corner - I've put 4 together to create a square shape that has more surface area for trapping bass and then put 4 more on top to extend from floor to ceiling. Please also add at least 6"-7" air space behind them to extend the working effectiveness down to lower frequencies. Remember that fibreglass filled bass traps maximize their effectiveness when placed at the one-quarter wavelength distance of the design frequency. So, for example, 100Hz has a wavelength of 135.6" (1130/100*12) so you'd need to have the bass trap out 33.9" (25%*135.6) from the wall, which seems like quite far; they are 24" wide so add an air space of 9"-10" and you're there. Alternatively you can buy a diaphragmatic bass trap that hangs on the wall and operates most effectively where the air pressure is greatest VS fibreglass filled traps that work best where air particle speed is greatest.

In summary, if I had your room, I'd likely do the following:
* move whatever traps you have or build or buy (making sure they're at least 6" deep) to the centre of front & back walls
* add bass traps to all four room corners from floor to ceiling
* place a rug on the floor between the listening position and the speakers
* alternate diffusion and reflective surfaces along side walls
* experiment with bass traps along the length and width walls placed at the 25%, 33%, 50%, 66%, and 75% marks of their lengths to catch the 1st through 3rd axial modes (which are the strongest [e.g. have the most energy] of the three kinds).
* add diffusion to your ceiling, starting with the side that is closest to the couch to attenuate reflections back towards the speakers yet maintaining the energy within the room to add spaciousness and soundstage height.

Good luck and read the book!

[aksharaajith]

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