yrtimed Posted September 18, 2009 Share Posted September 18, 2009 I hope it is fine with the rules to put a link to a topic in a different thread of this forum. I am asking for some help with room acoustics, and I noticed that this thread seems to be more lively than Home Audio » Architectural, where I originally posted my question. So, if you look here, please jump there (http://community.klipsch.com/forums/t/124672.aspx) and share with me your opinion. Thanks! Quote Link to comment Share on other sites More sharing options...
sunburnwilly Posted September 18, 2009 Share Posted September 18, 2009 judging stricktly by the link I say go for it ! Looks like a sound plan too meeeeeeeeeee ... Quote Link to comment Share on other sites More sharing options...
djk Posted September 18, 2009 Share Posted September 18, 2009 Quote Link to comment Share on other sites More sharing options...
yrtimed Posted September 18, 2009 Author Share Posted September 18, 2009 Thanks, djk! Here is my question: are all those suggestions for the room ratios implicitly assume that the speakers are placed in two corners sharing one of the longer walls, or not necessarily? If I exactly follow one of these suggestions, but place the two Khorns along a shorter wall, would that make any sense? Quote Link to comment Share on other sites More sharing options...
Don Richard Posted September 18, 2009 Share Posted September 18, 2009 Generally, long-wall placement is preferred, but if you have at least 3 good corners move one speaker and try short-wall placement. That may turn out to be the best in your case. Quote Link to comment Share on other sites More sharing options...
yrtimed Posted September 18, 2009 Author Share Posted September 18, 2009 Thanks! I have more questions. We just measured the height in the garage of the thought-to-be our new house, and the floor to beam distance is everywhere between 10' and 10'2". So, it seems like I can make a room with regular ceiling (not vaulted, as I originally thought) that would exactly fit one of the recommended height to length to width ratio. Of course, a room with flat ceiling would be somewhat cheaper to build and considerably cheaper to cool in summer/heat in winter. The question is whether the better sound would result from a flat ceiling (with all correct room ratios), or from an irregular vaulted ceiling? Also I would appreciate any suggestions regarding the materials to be used for the walls and ceiling. Or shall I just use something standard and later add some acoustical treatment if needed? Quote Link to comment Share on other sites More sharing options...
yrtimed Posted September 19, 2009 Author Share Posted September 19, 2009 Read several reviews, it seems like most people agree that Loudens "ideal ratio" of 1:1.4:1.9 is good (it also fits well inside Bolt's chart). So, I am thinking of making my room 10x14x19, flat ceiling. And later I might consider adding some inside acoustic treatment to the room. Any opinions on that choice? Quote Link to comment Share on other sites More sharing options...
Don Richard Posted September 19, 2009 Share Posted September 19, 2009 The question is whether the better sound would result from a flat ceiling (with all correct room ratios), or from an irregular vaulted ceiling? It is better to have a sloped ceiling than one that is flat. The slope would work best by having the tallest dimension to the rear. Since you are building new, it would be good to make the walls non-parallel, two inches per wall divergance should be plenty. These alterations will go a long ways toward stopping reflections and reducing the effect of room modes. Less room treatments would be required, and simple furniture, carpet, and drapes can be located to absorb early reflections. Your room would look more normal and less like a recording studio as a result. Quote Link to comment Share on other sites More sharing options...
yrtimed Posted September 19, 2009 Author Share Posted September 19, 2009 Thanks, Don, you answers are very helpful! You're right, before the room is built is the right time to look for the optimal shape of it. Ideally I would love to only add a couple of bookshelves in the right locations, instead of using more artificially-looking acoustic treatment panels. B.t.w., bookshelves with glass doors would be a bad idea, am I right? When you're talking about 2" per wall, do you mean making a room, say, with straight walls of sizes 13'10.5', 14'1.5', 18'11" and 19'1"? Structurally, it would be the easiest to have one of the angles equal to 90 degrees, and all the rest would be determined by that. Shall I make the "rectangular approximation" of the room corresponding to one of the recommended good ratios? In the case above, I was thinking about the 10x14x19 suggested ratio for rectangular rooms. Now, you mentioned sloped ceiling. Shall I, instead of having the height of 10' everywhere, have the ceiling linearly rising from, say, 9' to 10' (and adjust the room dimensions, in this case taking 9'6" as the height to put into the 10:14:19 formula)? The lower end wound be at the wall where the speakers will stand, of course. We have concrete floor in the garage, and I am thinking of making a wood floor in the listening room. Is it OK? Shall I use some special floor materials? Shall I use special materials to build the walls and the ceiling? We live in a quiet area, so I do not care much about noise isolation. Is it OK to have a window in the room? If so, does it necessarily have to be between the two K-horns, or may I put it on one of the side walls (maybe, compensating with some special acoustic treatment on the opposite wall)? Thanks a lot for your help!! Quote Link to comment Share on other sites More sharing options...
yrtimed Posted September 19, 2009 Author Share Posted September 19, 2009 I've made a new approximate chart of the room: Quote Link to comment Share on other sites More sharing options...
Don Richard Posted September 21, 2009 Share Posted September 21, 2009 Ideally I would love to only add a couple of bookshelves in the right locations, instead of using more artificially-looking acoustic treatment panels. B.t.w., bookshelves with glass doors would be a bad idea, am I right? Putting bookshelves at the rear (no doors) and loading them with various depths of books, CDs, vinyl, and assorted bric-a-brac will make great adjustable diffusers. Generally, you want to make the front "dead" and the rear diffused. When you're talking about 2" per wall, do you mean making a room, say, with straight walls of sizes 13'10.5', 14'1.5', 18'11" and 19'1"? Structurally, it would be the easiest to have one of the angles equal to 90 degrees, and all the rest would be determined by that. That's good. The idea is to keep things from being exactly parallel, as much as practical considering ease of construction. Shall I make the "rectangular approximation" of the room corresponding to one of the recommended good ratios? In the case above, I was thinking about the 10x14x19 suggested ratio for rectangular rooms. [Y] We have concrete floor in the garage, and I am thinking of making a wood floor in the listening room. Is it OK? Shall I use some special floor materials? Should be fine. We have concrete floor in the garage, and I am thinking of making a wood floor in the listening room. Is it OK? Shall I use some special floor materials? It is generally best to carpet the floor, or use a large area rug to kill the floor bounce. Shall I use special materials to build the walls and the ceiling? We live in a quiet area, so I do not care much about noise isolation. More rigid, thick walls will increase bass somewhat. Standard sheetrock over studs tends to absorb bass frequencies, and that may be desirable, so there is no easy answer for this question. You can always use an EQ for correction if things are not quite right. No matter what, I would fill the space between the studs with fiberglass batt insulation so that it is slightly crushed when the wallboard is installed. Build solidly so that there will be no rattles. Is it OK to have a window in the room? If so, does it necessarily have to be between the two K-horns, or may I put it on one of the side walls (maybe, compensating with some special acoustic treatment on the opposite wall)? Hanging thick, pleated, lined drapes over a window will cure the worst problems, and probably do the same on an opposite side wall to preserve symmetry. If the window is between the speakers, drapes over just the window will be OK. Quote Link to comment Share on other sites More sharing options...
yrtimed Posted September 21, 2009 Author Share Posted September 21, 2009 Don, thanks for the help! [H] Quote Link to comment Share on other sites More sharing options...
DrWho Posted September 22, 2009 Share Posted September 22, 2009 Can you post a picture of the entire space you have to work with, and then where this listening room fits within the garage? And is there an attic above the garage, or open rafters to the roof above? If the latter, could you indicate where the roof slopes? Quote Link to comment Share on other sites More sharing options...
yrtimed Posted September 22, 2009 Author Share Posted September 22, 2009 Mike, I plan to do something like this (assuming 14'x19' room): Here (1) is the listening room, (2) is a small library room, (3) is a corridor attached to the house and (4) is the garage leftover (that should grow back into a garage one day, by moving forward the car door). Currently all (1)+(2)+(3)+(4) is the 25'x29' garage. It does have sort-of-attic (there are beams, but no attic floor). Between the beams and the floor the distance is at least 10' (ranging between 10'3" and 10'). Quote Link to comment Share on other sites More sharing options...
yrtimed Posted September 22, 2009 Author Share Posted September 22, 2009 I looked into "Master Handbook of Acoustics", and played a little with this and this calculators. The following seems to be close to the best I can get, given my size restriction: It really makes sense to have vaulted ceiling, unless I want to place panels on it. The "naked" height is 10' (at least), I am not sure how much of it will be eaten by the construction, but aiming to the average height of 9.2' should be enough to get more than 1' gap between the high and the low ends. So, I would do that. Assuming that height=9.2' and given that I want the room length to be more than twice the height, I started from one of the nearby "recommended ratios" and adjusted it to cancel some coinciding resonances (they depend on the actual dimensions, not just the ratio). I got to the room size 9.2'x15'x21'. It is also "height-robust" in the sense that apparently, nothing terrible happens if I change the height between 8.5' and 9.8' (using the averaged height in the calculations gave me some feeling of uncertainty, so I wanted to compensate for that by checking what is going on in the wider range). Makes sense? Quote Link to comment Share on other sites More sharing options...
Istari Posted September 22, 2009 Share Posted September 22, 2009 If you put the Khorns in the corners of the 15' wall, your listening area (sweet spot) will be very close to the front wall. Placing them along the long wall will give you a better soundstage. I've tried both, the long wall is the best placement option. Quote Link to comment Share on other sites More sharing options...
yrtimed Posted September 22, 2009 Author Share Posted September 22, 2009 Thanks Istari, I see your point. Also the "official" recommended placement is along the longer wall. If I place the K-horns by the shorter wall, then probably the couch would be in a close to optimal position, but not the desk chair. On the other hand, if I put the speakers by the long wall then it would be impossible to find a decent symmetric placement for both couch and the table. Another issue is that if I build slanted ceiling then I would not really have a choice to try and compare placement by shorter vs. longer wall. I am not sure what shall I do... Quote Link to comment Share on other sites More sharing options...
yrtimed Posted September 22, 2009 Author Share Posted September 22, 2009 On second thought, everybody's saying that placing K-horns by a longer wall is recommended. So, given that I am designing a room specially for these speakers, trying to place them along a shorter wall would be rubbing the wrong way. Again, played with calculators and found that 9.3'x17'x20' is a good and "height-robust" ratio. If I go for it, I place the K-horns along the 20' wall. Makes sense?? Quote Link to comment Share on other sites More sharing options...
Istari Posted September 22, 2009 Share Posted September 22, 2009 That's what I would do. I would also try and brace the corners with added 2x4's for the first 4 feet on both sides. It's a cheap way of stiffening up the wall behind the speaker. It can't hurt! It's much easier to do BEFORE the drywall goes up! Quote Link to comment Share on other sites More sharing options...
yrtimed Posted September 22, 2009 Author Share Posted September 22, 2009 Istari, Thanks! I am not sure I understand what you mean by bracing the corners, could you please post a link to some picture? Are you talking only about the 2 corners where K-hors should be placed? Later: I guess, I got your point. When you say "the first 4 feet" you mean 4' up from the floor (and not 4' along each wall), right? Quote Link to comment Share on other sites More sharing options...
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