How do I build the best room


Yippee, I now have a partially unfinished basement with space for "The Room", and a wife who says I really should build one. I am hoping for some direction to some good online info on ideas for room design. I have reviewed the simple math on resonances and standing waves but sould like to obtain new ideas on mitigating the same. We are hoping to use room design/ shape in order to minimize required surface treatments. Approximate room dimensions are 8'H-15'W-19'D
Kevin
System- Dac1, Classe amplicication, Thiel CS5i and Magnepan MG20.1. (Speaker purchase has yet to be made)
be20
Well, what a nice collection of responses for a first post! Thank you gentlemen.
I am not surprised at the comments of concern regarding placement of MG 20.1s in the proposed room. Does anyone have experience with a pair of hot rodded 3.6's with external X-over and multi channel amplification? Comments on the Magnepan Users Group forum lead one to believe success may lie therein.
The dimensions, excepting the floor to ceiling height, are somewhat flexible am considering at least two opposing non parallel walls- most likely the long walls. This may cause difficulty with long wall placement.
I will have a dip in the eiling to 7 feet one inch to box in the Header and plan on treating it with an absorbtant product as it appears to be at or very near to the first reflection point.
Thanks again gentlemen for your expertise in this matter.
Kevin
The room is a little on the smaller side for the 20.1, but we did (successfully) put a pair in a 13.5 x 18 x 7.75 room. The planars don't have a lot of energy dispersed towards the ceiling and they don't have a lot of bass, so they can actually work reasonably well in a smaller room. However, at this size the engineering is difficult. The smaller the room the more attention needs to be paid to room modes, diffusion, reverberation times. Small rooms are very unforgiving to design flaws--but it can be done.
Kevin: I built my room in the basement also. The biggest problem I am having is eliminating the upstair noise. Footsteps being the biggest problem. So far have disconnected the ceiling from the floor truss and put in ceiling joist. Not even the walls are touching the floor truss now.Used 4 inches of rigid mineral wool for insulation. In the process of laminating 2 layers of half inch mdf with green glue inbetween and half inch of quiet rock with green glue inbetween it and the mdf. I had a drop ceiling and will be putting that back in with 1 pound psf mass loaded vinyl on top of the tiles. The channels will be treated with silicone where necasary so they will be quiet. Perhaps your situation is different but for me the upatairs noise was more than I could handle. Plus to much of the music was getting upstairs in my opinion. I read a lot on soundproofing. There are 4 things: number 1 mass , 2 isolation, 3 damping, 4 absorption. My room is 14 by 20 by 8. Treatments are some absorption on long wall and 21 inch diamiter 1.5 thick inch pipe insulation for bass traps about 12 inches out from rear cornor.Big pipe insulation. The room is fantastic sonically hopefully it will be quite enough in a couple of months. Hope this helps and hope your room works well for you. Jeff
Kevin, my new basement listening room is 8x15x19, so I may be able to offer some advice. Re standing waves, the room height vs room width may be the main issue. If any part of your ceiling dips below the 8' level (or if your floor is elevated anywhere), that will exacerbate problems in the 60-90 Hz area. But a combination of bass traps and digital EQ helps enormously. I am using five Corner MondoTraps from RealTraps and couldn't believe the improvement once I got them put in. That, plus judicious use of the notch filter in my Anthem AVM20 for movie material. You may indeed be able to utilize built-in DIY fiberglass for the direct reflections, but bass traps commonly need some airspace to do their work (i.e., place them in room corners).

Be careful about speaker size and type. If I had it to do over, I would swap out my von Schweikert VR-4jr's for high-end, stand-mounted monitors (maybe like Usher BE-718s) and a (good) sub or two. The VS's are too big for my space--they too easily over-excite the room. Also, I presume you have a cement floor; this will be difficult to spike floorstanders to--will really trash the sound. I am spiking the VS's to hardwood platforms that rest on the carpet, but this is probably not a final solution.

I am not sure what to make of the suggestion to put the speakers along the long wall of the room. You may want to try both the long and short wall; my hunch is that short-wall placement will give you more "wiggle room" in terms of trying different speaker placements.

General rule of thumb is to put some acoustic absorptive material behind the speakers, and acoustic diffusors behind your listening chair(s). The Echo Busters and RealTraps Websites have good diagrams and advice on this.
Let a professional do it. I have heard of companies that build studio's sometimes also do this kind of procjects. The have the experience and gear to do it. They have electronics that can map/determine the sonic behavior of your room. What frequencies needs to be damped. How much and with what delay you have echo etc etc.

Als I think it would be better to use a solid building material, bricks or concrete. I am not a fan of wooden houses.
Per Peter's input, IMHO the room size you are proposing may be too small for Maggie 20.1's. I listened over a few visits and various permutations of room treatments, mods and amplification while Peter did everything he described to make them work in his room. They sounded superb overall, yet they always felt like they needed more room to breath. The soundstage could never really open up in that space so the illusion was lacking in that way. It was there in spades in other ways. I'm sure they are capable of more, but I believe the room size was the real limiting factor there.
Hi Kevin,

It's great that you are designing a room from scratch! If you use dipoles, you may want to consider diffusion behind them. I've spent a good amount of time with dipoles in a room 14.5x18x11 (slanted ceiling from 8 to 14 feet), and you will need treatment. Maggies and other dipoles don't have a lot of side reflection, but plan to bring them out into the room a decent distance (e.g. 5 feet). Even more specifically, I'm writing about your choice of Maggie 20.1's. They are absolutely great speakers... a very natural sound. I've had them in my room. I've upgraded them with Mye stands, biamping with an excellent custom Xover, quite a few different amps... and my overall opinion is that your room may be too small for the 20.1's. They really need some room to breath. And while I found them to be more dynamic and spunky than my Quad 988's, they never really reached their potential in my room. I've finally gone over (back) to the other side of conventional (cone) speakers and am using Avalon Indras, which I am enjoying immensely. Do remember, it takes a lot to get the most out of Maggie 20.1's. Perhaps you might want to entertain the idea of a pair of Emerald Physics - which may fit the scale better. In any case, good luck and let us know how it goes.
I have a question about the first reflection point. I've been doing some research in preparation to build my own room from scratch. I had one of those "light-bulb" moment this morning while I was on a flight to Denver.

My room will be 14 ft (w) x 23.3 (l) x 10 ft (h). I have lay out the room per the speaker manufacturer's recommendation where my speakers will be about 6 ft into the room. And I've placed my couch about 8 ft from the back wall. With this information, I was able to determine the first reflection point and was planning to install some skyline diffusers. But what if I change speakers, or if placing the speaker closer to wall sound better? Or if I decided to move the couch closer to the backwall? All those things will change the location of the first reflection point, correct? So maybe rather than installing the diffusers to the wall, maybe I should place them on a rack where I can move them around?

Be20, I will share with you all the information I've collected so far when I get back home later this week.

FrankC
Google “acoustic room designs" and you will find a plethora of sites. Also, find a source for Owens Corning 705 rigid fiberglass - one of the most recommended and best materials for acoustic treatment. One of the most important things you can begin with is to install a dedicated 20-amp line (from your service panel directly to a high-quality outlet (at least hospital grade). Utilize a good "Romex" type 12-gauge wire. Read up on "corners" and in room bass loading. As you probably are aware, distance from the sidewalls is especially critical when placing speakers. If possible, you should design the room so that the system is set up along the long wall. There are some great pictures of dedicated rooms (including the construction process) on this site. You're lucky to have a space for a dedicated room. Good luck, and keep us all posted on your progress
Kevin; I have a room about the same size as yours 23 X 16.6 X 7.6 and you will need treatment. I would think at this point you have not built the room yet so you can build the treatments in to the walls. I think you need at the least bass traps in each corner and first reflection points . This can all be built in to the walls in the construction stage they could be covered with fabric and blend in to the walls and look nice. I would say bass traps in each corner will make a huge difference and I would try and include bass traps big thick traps in each corner . Will some of the walls be built next to a concrete foundation wall and some free standing then the more you need big thick bass traps . The room has such a huge effect on the sound and you have a chance to build it right and build it in to look nice so do not under estimate the importance of sound treatment you will love it after it is done. There is lots of info here and on audio asylum and the Rives site . Marc