If your going to spend the money and do it from the ground up, i would SERIOUSLY suggest either doing a TON of homework or contacting an architect with background in acoustics ( for that one room ). I would also be VERY careful as to the contractors that you use. You will need to make it VERY clear that any "abnormalities" that might appear in the blueprint are there ON PURPOSE. I've heard of architects designing rooms where the walls were slightly pitched and the building contractor thought that it was a mistake. Needless to say, the room and the walls were squared, which COMPLETELY ruined the acoustic aspects of the design.
As to electrical wiring, junction boxes, etc.... give Ray Kimber a call. He'll be glad to share his knowledge and give you some ideas. Since he manufacturers everything from wall outlets to wiring, he should have a good idea of how to do an entire electrical system for best results. Sean
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ozfly: what a fortunate man you are. i dream frequently of doing what you now have the chance to do for real. sean is absolutely right. it is no small undertaking to design an aesthetically and sonically pleasing room; it takes either expertise or much trial and error. i prefer the former. there are many things to consider, in addition to those you note. for example, you ought to choose very quiet heating and cooling sources and the kind of lighting least likely to cause interactions with your electronics. employ an expert in HOME acoustics. don't make the mistake in hiring an acoustic engineer used to designing sound enhancements for hockey arenas. ask and ask and ask before you begin. there are many who have knowledge to impart. one person to whom i'd recommend your speaking is alan goodwin of goodwin's highend in waltham, MA. i spent a rainy afternoon last november talking with alan about the design of acoustic spaces; he is a fountain of knowledge, gotten the less preferred way-- trial and error. do have fun and please try to convince your wife of the beauty of wool oriental carpets to cover a part of her wooden floors, especially in front of your speakers. i envy you your puzzlement. -kelly |
First, I basically agree with your room dimensions except that you might change the length to between 32 and 36 feet, to reduce standing waves in the ultra deep frequencies.
Second, put in as many dedicated lines as you can afford. My sound system has twelve dedicated 120 volt lines and two 240 volt dedicated lines for the stereo alone. Lighting and outlets are additional and separate from those. Be prepared to fight with the electrician on this, he will say it is totally unnecessary.
Many US amplifiers may be configured to run on 240 volt, and generally perform better ( fewer step up windings in the transformer, and half the amp draw for the same power ).
Consider using at least two, possibly three layers of five eights inch sheetrock on ALL the walls and ceilings in the room, and use liquid nails or silicone between each layer to eliminate flexing.
If possible, box the floor and walls into 18 inch squares in the framing process. This is also referred to as fire blocking. This almost completely eliminates flexing and will improve bandwidth and imaging.
Use liquid nails when installing the floor, and if pier and beam, use MicroLam beams, which are laminated (man made) beams that are epoxy pressure formed wood. Frame the MicroLam with galvanized brackets, in addition to the toe nailing with the nail gun, using plastic coated nails.
The best floor (under your proposed hard wood) is called sturdy floor. It is tongue and groove, and measures one and a half inch thick, is laminated (epoxy bound) and should be attached with liquid nails and deck screws to the Micro Lam during construction.
This will form a foundation that will not flex, squeak or vibrate, regardless of weight, placement or SPL produced by your system.
Put all the analog (or digital if your not an analog guy) on the high side of the electrical system. You can meter the two feeds from the power company, and determine the high side. Run the rest of the house on the low side, and separate the grounds between the two. I had a 200 amp (Square D) electrical panel divided into two sides, high and low. The stereo was all on one side in a solid row, and labeled. The rest of the house on the other side.
If you live were you can demand three phase, get it. Run your air conditioner (and / or swim pool equip.) on it. It will reduce your electrical bill and further remove noise from entering the stereo system.
If you can order a large "pass through" electric meter, DO SO. This type meter does not run the electrical feed through the metering equip (the meter read by the electric co.). Instead, there are solid copper bars that pass through the meter (same as your drop) and the electric companies meter is an Amprobe design. That is, it reads by "clipping" around the copper rods, rather than breaking the circuit!
You may have to fight for this type meter, and it is usually only in larger sizes. Mine is a 750 Amp. The utility is required to provide this upon request, provided you state that you intend to up your usage to require this at a later date. This may require meeting with a supervisor from the utility. It is usually a long wait on the phone, but in the end, is a FREE upgrade if they agree.
Separate grounds may be accomplished by using plastic AC outlet boxes, and running separate THHN ground to cold water pipe or copper ground rod. The rest of the house goes to the panel ground on the master box. If you are one that is concerned with ground potential, you may run a separate eight gauge ground from the panel ground, back to the same cold water pipe.
If you use metal screen under the wood floor and float the foundation (either pier and beam or slab) run a solid copper ground wire completely across the room, corner to corner, and attach to a ground rod before the concrete pour is done. This will form and RF cage, removing much of the received radio and microwave transmission that bombards our homes every day.
Do not install dimmers in the room.
Plan on spending some money on area rugs so you are not exposed to 100% hard wood floor.
Avoid any glass or doors on the walls behind the speakers and the walls immediately beside them.
Design the room with channels under the floor. PVC pipe is cheap, and may be purchased in every size. Place them between the equipment and speaker ends of the room before the pour. After construction, you have access to pull any size or brand of wire between your front end and mono amplifiers behind the speakers.
Fill ALL the walls, REGARDLESS if interior or exterior, with Owens Corning sound proof and basement R11 Fiberglass before installing the sheet rock.
I built a floor to ceiling bookcase in my listening room that attached to the foundation and roof structure. Within this space, I use solid Maple butcher block shelves two inches thick, and mount them with KV shelf bracket hardware.
This arrangement allows placement of stereo equipment where it is the most convenient and attractive, while providing adjustability for future upgrades incompatible with fixed spacing. This shelf has outlasted a dozen equipment changes, and saved thousands of dollars in (not) replacing racks and stands!
I have other suggestions, as I am currently doing this to my own living room. I know this all sounds a bit over the top, but I assure you that everything added together will not add as much to the price of your home as the price tag of a decent mid line amp.
In the end, these room improvements will have a decidedly larger effect on your listening pleasure, without becoming obsolete or requiring audiophile upgrades.
Later on, much of this would be difficult, if not impossible to implement at any price. Best luck.
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One thing I would recommend is to try to design the openings in the room symetrically. I have used rooms with unsymetrical opening into other rooms and due to varience in sound pressure levels it created a floating image that drove me nuts. Hardwood floors can actully be great if you use an area rug.
I would also wires several plugs wired directly form the fuse box using hospital grade wireing.
Good luck with the new house. I envy you buiding a specialized room. |
Actually, I WOULD NOT recommend you using 3 layers of sheetrock INSIDE the actual listening room, as the other gentleman suggested!!! you do't want the walls that unforgiving and stiff ideally! if you do put 3 layers, or the likes, you should do it on the OUTSIDE of the room, allowing for the room to have some give (instead of soundig hard and unyielding!), and let bass be naturally absorbed better, and simultaneously keeping sound out/in, etc.!!!
Anyway, i'm sure there's some good ideas that were mentioned here. And, as a custom home theater/room designer/acoustical engineer myself by trade, may I suggest you either get a professional to do the actual design work of the room (too easy to make big mistakes if your serious about your endevor, and a novice at the same time!?), or do lot's and lot's of home work!!!
Still it's hard to attack all the variables, if you don't have experience in to what does what, when you do this and that! Some things help, others make worse!...and so on.
There's no substitute for experience in this case (as many), and you'd do well to get some assistance from someone with the right expertise (my advice anyway)!
Actually, if you did want to get into it the correct way yourself, and wanted to do your own design work on this project, you should try to attend "Russ Hershelman's" work shop in San Francisco next month!!! I think there's still seats available, but the price is $750 (well worth it for what you're going to get, and what your investing in!!!). If you don't know who Russ Hershelman is, he's non other than the top Custom theater/room designer/engineer/ in the world!!!! He designs and egineers for all the biggest clients, and works with the biggest custom theater installers in the biz! Anything to do with designing sound rooms, and he's probably the man to listen to!!! He also runs articles in 3 top magazines (Home Theater, Stereophile's Guide to HT, and AV Interiors I belive (?). He's on going articles in most I think, and his knowledge in these area's is second to none!!(although I like to think I'm close to his league!!!...?). Anyway, best wishes on your endevor! Audioalexander.... |
I do not know the gentleman who you so deeply respect that does home theatre. The person who believes that multiple layers of sheet rock are not good.
My advice is not from my own experience, but rather from Russ Burger, the studio designer. Russ did Whitney Houston's studio, the acoustic work for Woody Allen and the new CBS recording studio. He is currently working on NFL studios, and in the short breaks between, has been kind enough to advise me on my room acoustics.
You are welcome to dismiss my opinions on audio, but as for acoustics, I prefer the advice of the guy that is responsible for music rather than theater. |
Ozfly,
I won't comment on Albertporter's or AVDcreations' recommendations on what to do. From previous posts, Albertproter has a room envied by many AudiogoNers, past and present.
However, both Sean and Albertporter have good thoughts on HOW. It is way cheaper to do things now than to put in something that is only half of what you want with the plan to "make it right" later. Besides, you never will. Most of the construction improvements will cost hardly more than the material upgrades if planned for now. Things like 1-1/2" thick subflooring or conduits run through the slab will be prohibitively expensive or impossible if not done now.
Also, please listen to Albertporter when he suggests that you carefully supervise the plans. Supervise the construction closely, also. There will be plenty of places for a contractor to cut corners with the unusual specifications that a sound room like this wil have. From the new construction I've seen recently, contractors cut corners on normal stuff already. For example, if your final design calls for laminating three layers of sheet rock on all the walls, you'll have to make sure that the contractor uses glue between the layers. If he's not watched, chances are he won't.
I hope I haven't offended any members who are contractors. This has been my previous experience. |
Sean, Kelly, Albert -- thank you very much for your responses. You are most kind in taking the time to lay out your thoughts. Alexander (I assume), thank you for your comments as well and for reaffirming the suggestions that I seek professional help -- my wife has recommended that for years, but that's another story;-) I have heard that you don't want too much reflection or uneven (frequency wise) absorption but don't know enough about the properties of drywall to comment. A friend of mine once built a small sound studio surrounded by sand bags, but my wife would frown on that. Albert is correct that my only purpose is for stereo as my more modest surround sound system is in another room. I'll check out the options for home acoustics experts, but please keep the suggestions coming. Thanks. |
There are no absolute rules in acoustic design. You can ask five different acoustic engineers the same question and get five different answers. On the surface this may appear confusing, but if you dig deeper, you'll find that each engineer has a design philosophy. Each element of the room and the reproduction equipment are designed to synergistically interact in in accordance with that design philosophy. You can get into trouble if you mix and match individual design elements from different engineers. If you decide to get professional acoustic engineering help, you will need to determine the engineers philosophy and make sure it's compatible with your goals.
The issue of surface rigidity is complex. In general, for home music reproduction rigid, but not overy rigid construction is best. Some wall flexibility can lessen standing wave problems. This will give you flexibility if in the future you switch to a different speaker with different low frequency tuning. In pro studios hyper-rigid wall construction is preferred. In a studio every element of the system is optimized to work together. The engineer knows exactly what speaker will be used, where it will be positioned and where the listner will sit. It's optimized, but it's somewhat inflexible. |
Ozfly, there are two completely different issues being discussed. Reflection treatment and good building procedures. The two do effect each other, but flimsy construction is not the correct way to control overly dynamic or flashy musical reproduction.
Light weight construction allows various materials to move and vibrate, competing with your speakers. This not only effects bandwidth, but the solidity of the imaging and soundstage as well.
Secure, solid walls will reinforce bass frequencies rather than allowing them to "pass through" to other areas. If the bass is too much with good solid walls, bass traps are the proper cure, not transparent walls.
I plan on building my room as solid as possible, and then treat the interior walls with several acoustic materials. Below are two sites that provide some of the material I plan to use on the ceiling and the two long walls. This is in addition to RPG panels, Tube Traps and mechanical isolation devices.
If you consider that using the Whisper Walls treatment, you can avoid the expense of tape, bed, texture and paint. Removing the contractors expenses for these materials will offset the expense of this acoustic treatment. These materials are designed specifically to improve listening. Again, best of luck.
http://www.owenscorning.com/around/sound/acoustic.html
http://www.soundcontrol.com/whisper.htm |
Lots of good advice here already, but as I quickly scanned it I didn't see anyone advising you to read books by F. Alton Everest, "Master Handbook of Acoustics" 4th edition, and especially "Sound Studio Construction on a Budget". The latter book has tons of useful sound treatment information and ideas for construction too. He and Robert Harley agree that nonparallel walls, while they achieve their goal, are not the only, or even the best, way to achieve that goal. Since the bad effects of parallel walls are quite easy to eliminate by inside wall treatment, I wouldn't contemplate that mode of construction, which I wouldn't trust many contractors to pull off. Good luck! |
ozlfly: i quite agree with albert about the importance of a sound foundation (pun intended) before applying acoustic treatment. two of the best rooms i've listened in have quite different foundations. the first applied construction much as albert has suggested but uses dual stud walls; this system employs room-within-a-room construction with two 2x6 decoupled stud walls, each covered with double thicknesses of 5/8" drywall and each wall lined with acoustic dacron "insulation." a 2" air void between the walls adds to the sound isolation in both directions. the second "foundation" is comprised of brick laid inside two-foot thick stone exterior walls (not practical, agreed, unless you've bought a cottage in the cotswolds). check out the chord audio listening room (in kent, england--no, not the cotswolds) for an example of a "brick interior" sound room:
http://195.40.133.90/website/main-gallery.htm.
i particulaly like the way the ceiling is treated. donÂt know how it sounds but it sure as hell looks great. again, have fun, you lucky..... :^} -kelly |
Kelly, I regret that I cannot apply one of these more complete solutions in room acoustics to my own space.
I have no doubt they are more advanced than what I have planned, but I believe the improvements I outlined will make a tremendous difference. The key word here is affordable. The people who are doing my acoustic did the Morton Meyerson Symphony Center here in Dallas. Obviously, my budget is poor compared to that masterpiece. Still, the acoustic work ( beyond the mechanical work outlined in my post) , will run another $15,000.00.
It would be nice to be able to do everything just perfect, and I would if budget permitted. I am certain that room construction and acoustics play as big a role in musical reproduction as the hardware we audiophiles pile in after the fact.
It is certainly less expensive to get the room right than spending for equipment in a never ending attempt to apply a band aid to the situation later. |
Here is a link to an article by RE Greene with some formulas for bass frequency reflections within a room:
http://www.avguide.com/how_to/index.html
You lucky dog. Charlie |
albert: i've absolutely no doubt that your sound room will rank among the most sonically pleasing i'll ever get the chance to experience. oh, i did tell you, didn't i, that i'm planning a little trip to dallas to participate in one of your tuesday night get-togethers, just as soon as you've got things all cranked up and dialed in? i have never heard anyone take more care than you in designing and overseeing your new soundspace. ozfly would be wise to emulate you. BTW, where are all those digital pics of the construction process you've taken with that whizz-bang new nikon? -kelly
ps- the chord electronics url in my last post won't work unless you leave the period off "htm" sorry. -fks |
Albert, an "rf cage" can only be achieved by doing what is called a "screen room". This is a room that is COMPLETELY covered in a tightly meshed conductive screen that is grounded, much like some "avid" ham radio operators do when building a "ground grid" in the yard around their house. In order for this to work properly, you would have to do the floor, ceiling, all walls, doors, windows, etc... Shielding certain areas between adjoining rooms or the floor above a basement MIGHT help if there were nearby devices producing low level RF, but since RF propogates by "floating", anything less than "blanketing" the room with a some type of ground shunted "shield" is just about useless. The RF will simply "float" around, above, below, etc... the shield and find its' way into the circuitry and wiring. Sean
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My previous floor was Terrazzo, and it's design employed metal strips embedded in the stone as a decorative trim, separating it into large squares. Under this floor was a network of what looked like chicken wire. I assume it was nailed to the original sub structure to provide strength, much like rebar in a foundation pour.
I had a huge problem with a particular radio station getting into my phono. I tried literally everything. Ferrite shields, moving cables, swapping cables, attaching and removing every ground from every piece of equipment. Even running dedicated grounds for the stereo only.
I could pick up this station so clearly that I could make out announcements. Finally, in a test where I went under the house and attached a ground rod to the metal in the floor, the problem was totally eliminated!
I could literally turn the radio station on and off by removing and reattaching this single wire to my floor. No other ground in the system had this effect, nor could they eliminate the problem. This experience leads me to believe that a ground should be attached to ANY metal installed in the floor of a dream room, least it become a nightmare room like I had.
Your definition for a RF cage is probably more accurate than the application I just described, none the less this trick does the job. This should be applied to one's dream room regardless of the name used to describe it's ability to potentially clear RF signals from the music. |
Kelly, I did not mean to ignore your comments. If you are serious about a visit, I would be pleased and excited. I am willing to do anything to make this a reality, including finding you accommodations and picking you up at the airport.
On the photography, I have a good number of photos during tear out and reconstruction. These have all been with my new D1X Nikon. The quality is there, but the subject matter is downright ugly. The exposed earth visible in most of my living room makes for a less formal look than I am accustomed to.
I tease with my contractor we need to mop up, and he says the has tried, but he mud just won't come up. It's difficult to maintain a sense of humor crossing this area each morning to make coffee in our kitchen. In the end it will be beautiful, I just need to keep reminding myself. |
The good news is that there are a lot of great ideas here. The bad news is that I'll have to spend some serious, but fun, time following up on them and learning. The tricky part will be sharing this with my wonderful wife --- "Remember when we talked about the right room dimensions and corner treatments ... well, there's a little more to it than that ..." Oh well! Thanks for all the great advice. It'll take some time to research it but I'll follow up down the road with an update and would certainly be happy to invite you all to Charlotte for a listen once this is done.
Always happy to get more ideas, so keep them coming. |
Albert, thanks for sharing that info. Your results are pretty irregular yet undeniable. I guess that you changed the impedance enough by using your "ground grid" to "detune" / alter the impedance of that area. Not many people would have thought of doing such, so that speaks highly of your creativity and willing to "tweak". Obviously, your results speak for themselves. Sean
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Once again, thanks for all the great advice. My house is now being framed and the job is being supervised by the man who built Billy Graham’s recording studio. First off, I did have to compromise to make this both a listening room and a living room. At the end, it will still be better than I deserve (I hope). Here are the specs:
Dimensions: 32.33 X 20 x 12.08 (the rear wall has a 5’ opening on the left that adds another 23’ to the length and the right wall has an 8’ opening in the center that adds another 18’ to the width). Should I open up the rear wall another foot wider?
Floor: Manufactured support beams 16” on center with no more than an 8’ span. 3/4” super dense (50 year) floor boards nailed and glued. Another 3/4" will be added for hard wood. If there is any give at all, we will screw the floor board to the joists prior to the hard wood installation. Will have large area rugs.
Left Wall: A total of 16’ of glass (six wood and aluminum clad, low e windows) and a stone fireplace in the middle. 2x6 construction, 16” center to center, with stucco on the outside. 5/8” drywall.
All Other Walls: No glass. Offset 2x4 construction on a 2x6 base with each “wall” (inner and outer) built 16” center to center. Insulated. Using 20 gauge hat channel parallel to the floor (debating whether to go 16” or 24” center to center – thoughts on this?) to which a double layer of sheetrock will be screwed. Sheetrock in the room will be 1/2” (vertical) glued and screwed to 5/8” (horizontal) which is joined to the hat channel. Sheetrock on the other side of the wall is 5/8”. Is it worth the money to go to a high STC rating for the 1/2” sheetrock facing the room?
Ceiling: Same as “All Other Walls” in construction. Will also have 3/4" of gypcrete poured over it (not on it directly). The border of the ceiling, all around, is trayed (2’1” drop – 90 degree angle to the wall for 2’, then at a 45 degree angle for another 18” to reach the final height of 12’1”).
Built-in: About 15’6” wide and 8’ tall. Jutting out to 30” deep in the center (48” wide) and then dropping back to 2’ deep for the base unit with shelves above at 1’ deep. Height drops to 7’ in two equal increments from the center unit. All wood with some glass in the middle (is there a less reflective option that lets infrared pass?). My amps will be in the end base units with a mesh in front (rather than a door) and, probably, a remote fan pulling air through 4” vents in the back.
Acoustics: No pressure zone. Standing waves in the 12-105 Hz region (adding an active takes it to 210 Hz). First order standing waves are within 3db at 87 Hz & 140 Hz (plus 227 Hz which should be outside of the region). They are within 6db at 56 Hz, 174 Hz and 197 Hz. These are really good results compared to the calculations done by changing increments on any of the dimensions up to two feet. Using conservative absorption coefficients, reverb times are 1.5 seconds at 125 Hz and between 0.4 and 0.6 seconds between 250 and 4000 Hz. Reflection levels and delay times compute well – though the final proof is in the pudding.
I was not able to slope the ceiling or walls though that would have improved the acoustics (this was one of the design tradeoffs).
Any additional ideas? Comments on my questions (24” vs 16” on the hatchannels and the rear wall opening width)? Electrical design to come – have not yet met with the electrician (will try to stay away from romex, use 10-12 ga wire, use separate grounds). Thanks in advance for your comments or questions. |
