Clueless seeks basic room acoustics help for K-horns

[matt giddy fruit]

Hi guys

Just renovating my house and whilst everything is stripped back raw, I'm wondering what I can do to the room to optimise the sound for the ol' K horns.

I tried calling some acoustic engineers but they didn't seem too interested in a project of this size and then I thought of you guys!

Any ideas on the following would be much appreciated...

1. Are there certain products/materials that can be used to construct/line the walls in order to optimise acoustics?

2. Do these materials also provide soundproofing or are two separate solutions required to both improve acoustics and minimise sound leakage?

3. Should the same materials be used on the 'corner' walls as on the wall that faces the speakers?

4. Does the ceiling need to be treated / covered?

5. Any other basic acoustic fundamentals to abide by?

The room is 7.5M (K horn wall) by 5M. Layout needs to be that way round for various reasons.

Floor is recylced timber. Presumably (and yes I'm showing my ignorance here!) laying down a rug will improve the sound?

Thanks as always guys

Timber foor

Dimensions for the lounge which doubles up as the listening room are as follows:

W5m x L7.5M

[Groomlakearea51]

1. Are there certain products/materials that can be used to construct/line the walls in order to optimise acoustics?

It can go from simple to outrageously complex and expensive. Most effective for the cost is to use a good grade of insulation; the higher the "R" number, the better; not only for dampening, but for.... insulation and by consequence utility costs. There is nothing wrong with using standard drywall. Should be a good grade, not the el-cheapo less than 1/2" thick. Make sure it's USA made.

For the long wall on which the K-horns are placed, some acoustic foam panels should be used in the center area about 5-6' wide and extending up to the ceiling. There are some very nice expensive ones and some effective simple ones. Before you run out and buy acoustic foam "absorption" or "diffuser" panels, try hanging a blanket in that area and see what happens to the sound.

2. Do these materials also provide soundproofing or are two separate solutions required to both improve acoustics and minimise sound leakage?

Provides both. Sound "leakage" is going to be a function of the walls and insulation as far as leakage outside the exterior of the house, but much will depend upon the door to the interior of the house, where it is located and the geometry of the rest of the house. Little you can do in that regard. If it will be a problem, use a heavy, solid core door, keep it shut when playing music louder than what the rest of the family will tolerate. Place some acoustic foam panels on the rear of the door (inside the music room. That will tend to keep the sound in the room.

3. Should the same materials be used on the 'corner' walls as on the wall that faces the speakers?

Yes. Generally no reason at the "home" level to use double layers of drywall, etc.

4. Does the ceiling need to be treated / covered?

Depends. Usually not practical in multi-purpose rooms (as in the living room...). You can use some "egg crate" diffusers in the center of the ceiling close to the wall on which the K'horns will be placed. For the size you describe, you will need about 18 square feet.

5. Any other basic acoustic fundamentals to abide by?

I have noticed over the last 33 years of owning (moving all the time in the military) K'horns is that they always sound "horrible" in an empty room. The speakers, being so efficient, simply go crazy bouncing ecerything off the walls and floor until objects are in the room to diffuse and absorb the nodes.

The worst problems come from resonance and distortion from sound bouncing around all over the place. The "first" reflections are not a problem as that is what makes the room sound "live". It's the second order reflections. You will want to have somthing on the side walls diffuses/ breaks up the sound waves, and something that absorbs sound on the rear wall. Easy way is to use bookshelves on the sides, and nice wall hangings, etc on the rear wall.

Get a tall dressing room mirror (el cheapo kind from wallmart...) place it on the wall about 36" out from the side of the K'horn. Turn it at a 45 degree angle from the wall towards the middle of the room. Go stand and look at it. Then walk backwards to the opposite wall. That's were the majority of the bad reflections get started. From that wall turn it 45 degrees towards the rear wall. Same thing. Treat those culprit areas.

Use boxes of "stuff", blankets, etc and get something in the opposite corners. As far as the rear wall goes.... boxes stacked assymetrically, stacked blankets, etc. Try putting stacked boxes and some blankets in the opposite rear corners and across the rear wall.

A cheap "cheat" for this is to go to your local liquor store and find out when they unpack deliveries. Grab about 20 boxes of varying sizes, pack not-in use seasonal clothes in them and use those as the diffusers and absorbers. until you have it "under control" and you are ready for nice "decor"

Rule of thumb is diffuse the side walls and absorb the front center and rear wall.

There are also a couple other "tricks", especially if it's going to be a music room. The first is to get something that will absorb bass up in the four corners next to the ceiling. In my case, my side wall bookshelves are 8' tall and with mexican blankets up in those corners, there is no unwanted bass resonating. Same thing applies on the corners above the K-horns. That may not be practical, but if all else is pretty much solved, that won't generally be that noticeable.

.....laying down a rug will improve the sound?

Depends on the room after you have it "assembled". Have a nice throw rug, a couple of "beanbag" chairs handy and when listening try placing the rug at various distances from the the K'horn wall. Same thing with "comfy chairs", etc.

These are only some basic, simple things you can do without going into mega-buck engineering ventures. Also check the "architectural" section of the forum. Lotta' great ideas and pictures in that section.

Hope that is a start point for you.

[H]

[TheEvan]

Offhand, I don't think wall construction will be a factor as long as it is stout enough to function as a wall.

A rug might help, but that depends on how the rest of the room is outfitted with furnishings, accessories, bookcases, etc.

7.5m is quite far apart. Your setup would benefit, probably significantly, with a center speaker, preferably a LaScala or Belle, though a Cornwall or even Heresy will do.

[sebrof]

3. Should the same materials be used on the 'corner' walls as on the wall that faces the speakers?

Yes. Generally no reason at the "home" level to use double layers of drywall, etc.

I reinforced the corners my KHorns sat in with 3/4" MDF boards and experienced tighter bass, similar size room. Maybe it depends on what the wall is made of and what's on the other side. In my case in one corner it was a brick exterior both walls, the other was brick exterior and a closet. Drywall.

Matt - What is on the other side of the walls/corners (i.e.: exterior of the house, adjoining room, etc.)

Personally - If I were in there anyway, I would certainly reinforce the walls/corners where the KHorns were planned to be. But that's just me.

[MikeFord]

The key to sound proofing is to make sealed layers, even small openings let through a lot of sound. Everything else, kinda depends on the room details.

[pite]

Sometimes ago, I was looking into this, and while googling, did find few links where 'audio enthusiast' were treating their room/area. They had different things in mind such as sound deadening, insulating, good sound etc. so that their system would sound good and then sound wouldn't travel beyond a desired boundry (mostly room walls, ceiling, floor). I would suggest to google and check them out and see if something is of help.

[matt giddy fruit]

Thank you very much everyone for your help - and in particular of course Groomlakearea51for what must be $$$s worth of great advice. I love this place! []