Curtians vs Soundboard

[m00n]

I will eventually be trying to improve the sound quality in my theater, I am considering using a) soundboard, curtians. Soundproofing aside, will curtians work as well as soundboard for helping with sound bouncing around my theater?

Would soundboard with curtians be overkill? I really think I want to put soundboard on everything to help with soundproofing, but at the same time, I would like to have curtians for decor. Other than curtians, another option I have considered would be to wrap the soundboard with some nice fabric. However, what gets me there is how I would mount the soundbaord to the walls and ceiling such that there would not be any screws showing through the fabric.

Any ideas?

Thanks all.

[cluless]

if you cover the soundboard, fabric trim or cording can be hot-glued on to cover the screws. Better still, put up the wall board then upholster the wall (easy). That way it's easier to change.

[m00n]

That is true.... Good idea.

What I was thinking though is that I would wrap the board with fabric before hanging the board. This way there would be no ugly seams. Yes, there would be seams between the soundboard.....

Soundboard is not that heavy, I guess I could glue them in place.

[m00n]

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On 10/21/2002 2:29:08 PM cluless wrote:

Better still, put up the wall board then upholster the wall (easy). That way it's easier to change.

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If I did it that way, how would you suggest hiding seams?

[cluless]

The fabric panels would have to be sewn together prior to hanging. If a good pattern match is made (like in wallpaper) and the seams are nice and flat they won't show unless you are looking for them. Trick is to get the seams nice and straight vertically, the wider the wall, the more difficult it becomes. Then you just staple the fabric at the top and bottom and add trim.

For a very wide wall it would probably be easier to cover the boards, like you said initially, but it would be a beast to change.

I dont have any idea what the trade-offs would be for sound damping and cost effectiveness.

[justin_tx_16]

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On 10/21/2002 2:29:08 PM cluless wrote:

if you cover the soundboard, fabric trim or cording can be hot-glued on to cover the screws. Better still, put up the wall board then upholster the wall (easy). That way it's easier to change.

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we are doing that, it is some corky fibery board with the walls upolstered for my dad ht, which don't get me started on the status.................

[m00n]

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On 10/22/2002 12:16:55 AM justin_tx_16 wrote:

we are doing that, it is some corky fibery board with the walls upolstered for my dad ht, which don't get me started on the status.................

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No... Actually I would like to hear about it. Is he having troubles, what is working what is not working

[justin_tx_16]

here is what happened. we were dead set with getting everythng installed. but then stupid auio demeisons came in the picture and screwed things up. they put in the worng speaker wire, the wrong placement for it, etc etc. they charged double what it was worth so we threw them out and i took over. i decided all klipsch etc etc. we had a $42,000 budget, after treating the room. we had the contractors lined up to do work for this summer... then one got cancer, the wall guy, so we had to pause everything else. he is still not better, good luck!, so we are finding another guy. one new guy was supposed to come out in mid october, never heard from him. everything is designed, ready to go. we have put a like $8,000-14,000 deposit on everything, we own about half of everything as it is but hav eno where to put it, tweeter is just holding our order and downpayment. (that may have been a mistake...)

so we are waiting for the room to be finished, not much different than when i posted pictures so so long ago.

[m00n]

Well damn boy, your young.... Get giggy with that hammer and start slinging some hammer and nails.

[justin_tx_16]

...been there, done that... hopefully never again we used to buy fix-em-up houses, after a few of those we decided to get one built for us. except even that is a major pain

[WMcD]

The story is a bit distressing.

In reading the beginning of the story I was urged to say that some heavy curtains, some good carpeting and overstuffed chairs, would do as well as acoustic panels.

The panels described seem to me to be far over rated, and ugly. I was thinking about the acoustic tiles with little holes and the criss cross expanded plastic. Home owners are sold this stuff at high prices for material and installation. Gives one pause.

But what do I know, so why chime in. Further, if you have a competent contractor and this is all in a morgage, the cost is not that great. Let the experts do their work.

The outcome, though, argues to the contrary. When I get a chance to build a killer listening room, I'm gonna do it myself. No matter how large my errors, it is better than turning things over to an outsider.

Gil

[m00n]

Yep, and it's a labor of love.

[Colin]

I have yet to see what frequencies the panels are supposed to dampen, everything I have seen so far affects the very highest frequencies, only really large and thick panels can affect some of the more crucial frequencies - which is why rooms end up covered in the stuff from head to toe, it looks good, but I have yet to see evidence that the fancy panels make a huge difference, so I say go with thick curtains on all three walls and big comfy chairs and a thick rug ...

[Doc Holiday]

exactly what is sound board? does it help to reduce rattling, because if it does I may need to invest. also how much does it cost..... thanks

[Colin]

Part Express currently has a big box of foam diffusing pads for about $45, should be enough to dress up most average size rooms. Note, however that the foam pads are rated to dampen mid and high frequencies far more efficiently (97%) than they reduce low frequencies. If you have a mid-bass bounce or suck-out, if can be very hard to correct in a room without a large bookshelf, or heavy curtains and carpets. The sound traps and tube traps dampen the audible mid and upper frequencies. This is why their effect is so noticeable.

The foam pads should be placed at the mid-point of reflection between you and the loudspeaker. From your ideal listening position (the sweet spot), have someone literally take a mirror and slid it along the wall and ceilings. When you can see the loudspeaker from your sweet spot, that is where the foam block should go. It minimizes the frequency bounce caused by reflection of the sound wave. Dampening material is often applied behind the loudspeakers, which is usually the easiest area to place something, but this can reduce soundstage and imaging (since dampening material reduces high frequencies easier than low ones).

The nice thing about testing dozens of loudspeakers with several different amplifiers in the same room is that you quickly get an idea of the room characteristics. If all the loudspeakers generally show the same rises and dips in the same frequencies when placed in the same spot, you are probably looking at the rooms unique anomalies. Of course, this is not possible for everyone, but there is something that you can do. You can do a clap test.

In fact, before you adjust any room, I would perform the clap test. Any room where you go to listen to loudspeakers, you should test with a simple clapping of your hands. All that is required is one clap at a time. Clapping gives you an idea of the sound of the room. Creating a clap with your own hands gives you the same note, with the same amplification, that you can take with you into any room. It is always the same. Listen for the tone and the echo. That will tell you about the room.

As you apply more bookshelves, curtains, carpets and foam blocks to the room, keep repeating the clap test. The echo should diminish, but the clap should not become dull. Using the mirror reflections, it should not take a lot to reduce the echo of high frequencies in a room.

Bass notes however, are more of a challenge. They bounce around the room. Where the bass notes cross each other, they cancel each other out, creating a dip, or a suck-out, in that frequency. This dip is a function of the length and width of the room. Square rooms suffer this problem more than any others: there is no where for the bass wave to go. It bounces off one wall and cancels itself going in the other direction. Padding the room to prevent bass dips is tricky, but using the mirror technique to estimate the points of reflection is a good start.

[artto]

I built an entire room around my Klipschorns in the early 80s & the room has undergone a number of revisions. You & other readers might benefit from what I did & what I learned from my mistakes. The room has been published in several audio magazines over the years.

First things first. Ideally.you need a room with the proper proportions to achieve uniform distribution of eigentons (low frequency room modes). The ratio is 1: 1.26: 1.59 (called the Golden Mean) (see Klipsch Dope From Hope newsletter Vol9, No1 Feb 1968). It doesnt have to be exact. And rooms outside of these proportions have been known to sound good. Use the long wall for the stage. It makes a dramatic difference & you may even find that you dont have to turn-it-up as loud.

Another trick you can use is the Half-Room Principal (Room Dimensions for Optimum Listening and the Half Room Principal, IRE Transactions on Audio, Vol AU-6, No1 Jan-Feb 1958, pp 14-15). For instance, my room is 27 wide. A 42Hz note has a wavelength of aprox. 27. So based on the longest dimension of the room, the room will accurately convey the full wavelength of a 42 Hz tone. But based on the Half Room Principal, you can expect a reasonably flat room response down to 21Hz (21Hz=54 wavelength. 54/2 (one-half of the wavelength)=27.

If you take this one step further & use the diagonal dimension (which you can do with K-horns because of their corner placement & 45 degree angle toe in) it works even better. My room has a diagonal dimension of 32 which ½is one-half of 64. 64 puts you at about 17-18Hz. My system has measured down only 9Db below 20Hz with no electronic EQ. Not bad for folded horn-loaded speaker of this size. And in fact, that puts the K-horns at about 95Db/watt below 20Hz. Much better efficiency than any of the sub-woofers or so-called flat audiophile speakers out there.

A dimension you want to avoid is 19 (or multiples & fractions) thereof as it is the wavelength of 60Hz (electrical hum).

A quiet room is a good room. Avoid exterior windows if you can. In my room, I isolated all plumbing (sump & ejector pump plumbing too) from the frame of the house. The plumbing is also insulated. Same thing with any forced air vents. If you can isolate the rooms ceiling & walls from the structure of the house, do so. I didnt have the luxury of doing that. Remember that wall mass & no air leaks has more than anything else to do with blocking sound.

In my room, I applied silicon beading to the interior of the outside wall studs. Standard R-19 wall insulation between studs. Over the studs I placed ½ ½1/2 inch Celotex http://www.us.bpb-na.com/products.html rigid insulation board. Sealed the joints with silicon beading. Silicon beading over the Celotex where the studs are located. Created a 1 air space by putting 1x2 lath over the studs/Celotex. Repeated this process again. Then applied 5/8 sheet rock (Gypsum wall board). Since my room is only partially below ground, the upper wall exposed to the outside received an additional layer of Celotex with a 2 air space between it & the wall. Similar treatment was done for the ceiling. Ilbruck (maker of Sonex acoustical products http://www.mhtc.net/~lowey ) now makes a product called ProSpec Barriers which I would recommend using between the layers of the wall & ceiling.

I also heavily reinforced the corners for the Klipschorns, from the corner, to 8 out from the corner. I used a staggered 6-12 stud spacing, both horizontally & vertically to eliminate any wall resonances. I then made 4 plates out of 2x12 wood, fit into the studding & secured them & the wall, tightly against the foundation. I made a corner fitting out of 2x12 to fit securely & air tight (use foam weather striping) in the corner for the tail board of the Klipschorns to be secured onto. The corner board is secured to through the wall to the foundation with 10 ¼1/4 inch lag screws. The tailboard of the K-horns are secured with 8 ¼ ¼1/4 inch lag screws to the corner plate. The K-horns are sealed air tight into the corner with weather stripping foam.

In regards to electric, have everything on its own circuit. Im not sure that 20 amps is enough nowadays. Obviously this depends on what kind & how much equipment you have. Tape decks for instance can draw a lot of current because of the motors in them. Make sure you use an isolated ground for that circuit, isolated from the rest of the electric in you home. Ground the system at only one point, preferably from a regulated power supply that everything else is plugged into. Float all the rest of the ground connections on your equipment using a 2-prong adapter so that the ground(s) seeks their own level & does not produce any ground-loop hum. If you are using light dimmers, make sure they are the kind that have RF filtering. No fluorescent lighting.

Now for acoustics. The Klipschorns do not like dead areas around them, so forget that dead-end/live-end room stuff. It doesnt work with K-horns. I use large polycylindrical surfaces made from ¼1/4 inch tempered Masonite (a wood-based fiber hardboard) (cheap) bowed to 12 on larger ones (4x8), 6-9 inches on smaller ones. These can be painted to match room décor. Behind the cylinders I mount Sonex acoustical foam on 3-6 standoffs on the Celotex behind the Masonite so the Sonex can capture sound more effectively from all directions & angles. This produces a room with very well distributed/dispersed middle & high frequencies. The larger polycylindrical surfaces help to damp bass resonances & break up standing waves. The principal here is to allow the room to be relatively live at low volume levels. But as the sound levels increase, more & more reflected sound gets trapped behind the cylindrical Masonite panels & gets totally absorbed by the Sonex & Celotex behind it so the room does not acoustically overload due to increased reverberation time at higher volume levels. A simple thing such as clapping your hands can be very useful in locating hot spots or ping in various areas of the room which will require sound absorption or dispersion. Likewise you dont want any dead spots either. These Masonite panels can create quite a dramatic appearance, so be creative & experiment. Keep in mind that the bow in the Masonite panels will tend to push the walls of the room in making the room seem somewhat smaller. This can be overcome by the use of lighting to highlight the depth & curve of the panels.

[m00n]

Thanks colin and artto. Great information. My remodel will start in Janurary. I am taking 2 weeks of vacation and spending it all on working on my theater.

If your in the Portland Oregon area, cmon over and help sling some hammers.

This project is actually turning out to be a huge mess for me. I am torn between trying to get the absolutly the best sound possible out of the room VS. simple elegance. My wife really wants to decorate it up nice with curtins, pillers and sconces.

Now, going with a nice elegant look does not boad well with some huge peice of sound absorbant material right in the middle of the wall.

Thus, this is where I am heading with my thoughts....

--=={OPTION 1}==--

Soundboard wrapped in a nice material on the two ends of the theater, as in behind the screen and speakers from floor to ceiling, and on the wall opposite the speakers again floor to ceiling. Then soundboard down the lengths of room on the side walls. This however, would have soundboard only 4 feet high again wrapped in the same nice material.

Reason for not going floor to ceiling on the side walls is to allow for some liveliness in the room. Don't want it too dead.

--=={OPTION 2}==--

Soundboard on the two end walls. Nice material on the end with the screen and speakers, however a nice thick curtian on the back wall floor to ceiling.

Curtians about 6 feet high on the side walls from front to back. Again not floor to ceiling to keep some liveliness in the room.

I am far from being someone who is a professional at all this. My ear for this is amature to say the least. I don't have any measuring equipment or anything. however, the idea of using a mirror was the first solution I have heard that did not involve some fancy equipment, or simply listening carfully. I just don't know what to listen for....

So, I have come up with those two ideas based on reading other peoples posts in other forums.

Any suggestions, ideas? Goods bads?

Again, thanks

[NOZ]

mOOn,

You are on a parallel path as me. As you know I finally finished the main basics of the room, and the tweeks are coming.

My idea is to put small sound boards on the walls opposing where the speakers are aimed. Small meaning 2'x 3'. This will take a lot of explaining so I won't go into it here... We'll talk.

Sean

[m00n]

Noz, ya anytime you wanna trade ideas. Do you have either MSN Messenger, or AOL instant message account? If so, send me a pm here and we can trade account info.

[fini]

Moon, I hope you don't mind me barging in on your topic (I have issues with this topic, too...my HT is in a weird, multi-purpose room)< but I've got a quick question. My 14 year-old daughter has asked for AIM to be installed/downloaded onto my iMac (so she can dominate the computer, AS WELL AS the phone lines). Is it free? Will it work on Macs? Are there downfalls? Thanks!

fini