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New Construction Acoustic Design & Consulting

I need a professional consultant to work with my architect to help build as perfect a listening room over my garage as possible. RIVES is one possibility but I don't want to spend 10K just for the consulting work. I would like to build in as much sound isolation and room treatment as possible like that done for this person:
http://www.positive-feedback.com/Issue16/lavigneroom.htm--

Could I use ASC as a primary consultant and RIVES for after the room is built to do the final touch ups and room treatment? They only charge $100 for the engineer to help render sketches and make suggestions for the contractor.

acousticsciences.com

I would need detailed plans so that the architect would know how to impliment the built-in bass traps etc. I would need help with the specifics of window and door selection (materials) and placement, room dimensions, ceiling slope, floating floor, isolation etc... Please also see the list of ideas below. RIVES charges a fortune to render drawings based on a computer modeling system. I am not sure all of that makes sense until after the room is built, furnished and then tested, but certainly it is advantageous to build in as much acoustic isolation and treatment as possible from an aesthetic and cost perspective. Please comment on some of the suggestions below:

Room sizes

13X21X8 Feet
14 X18X8 Feet

windows o.k.
According to Dave Wilson

1. pitch ceiling height lower over speakers, higher over listener
2. Build bass traps into the wall
3. Corner loaded bass traps
4. Bass trap all four vertical corners and the ceiling perimeter corner with a soffit bass trap
5. Room dimensions:
Must over-size room by minimum of 6 inches walls, floor, and ceiling to allow for buildouts for acoustic treatments and sound isolation
A. 13-15 feet wide by 15-23 feet long
B. Room height 7-9 feet
must account for additional height of "floating floor"
C. Wall/stud resonance treatment and constrained layer damping: 1. Sandwich two layers of sheetrock. ? Gyproc Soundbloc 1.5 soundproofing plasterboard 2. Suspend sheetrock off studs by screwing into resilient metal fir strips called "z-metal" or "RC-1" 2. Visco damping material {1/16 " thick double sided adhesive visco-elastic sheet} is applied between the z-metal and the first sheet rock layer and a second visco-elastic sheet between the first and second layers. In place
of double sided adhesive visco-elastic sheet, can 100% glue to both sides a layer of sound board {firtex or celotex}. ? Staggered studs. The ceiling must be treated the same way.
D. Locate entry door behind the listner but on a SIDE WALL {nowhere near the speakers since the door will raddle} NOT ON A BACK WALL AND not flush to the corner and at least 2 feet from the corner. Door cannot rattle? Heavy acoustic door/frame?
E. Windows are very tympanic and should be avoided. Tall narrow windows are best.
Must not use standard thermal type instead use 2 layers of thick laminated glass [like that used for glass shelving in stores] separated by at least 4 inches of air space. The air space must be vented into the wall cavity. Set the glass into a bed of visco-elastic damping material. The glass sheets should be of different thicknesses.
F. Lighting should be subdued, indirect, and dimmable. Do not use standard wall dimmers since they will often hum or buzz. Use a variable voltage transformer. Consider low voltage lighting. Do not use ceiling cans, they rattle. The best light has a ceiling bezel and lens of thick rounded glass. Consider creating a false ceiling to hide projector, cabling, HVAC
ventilation big problem if room needs to be airtight to insure adequate sound isolation and room damping from the rest of the house
G. Address side wall, rear wall, and ceiling reflections which are determined by speaker placement. Room dimensions must account for acoustic panels
dbk
stehno
1,453 posts
 
I would prefer the 13 x 21 x 8 ft dimensions.

A lot of the points you mention above are good and definitively should be considered in the new room.

Assuming that the room is built well with all the basic elements(many of which you already mention), you may not need any special acoustic treatments.

I say that because based on my experience, speaker placement plays a far, far more significant role that room acoustics and treatments. In fact, I think it was Robert Harley of TAS who said a few months ago that proper speaker placement provides far greater benefit than any room acoustics. Or something like that.

Some to many say room acoustics makes up about 80% of the sound you hear. I'd guess it's probably more like 20% with the room/speaker interaction making up perhaps 50% of the ultimate sound you hear. I'm guessing but I'll bet it's a lot more accurate than the 80% rule.

One thing I would consider adding to your list is a beamed ceiling where the beams are spaced perhaps no more than 3 or 4 ft apart starting at the front (behind the speakers) and then perhaps every 3ft going toward the rear of the room.

Oh yeah, when it comes to furnishing you might consider heavy clothe/cushioned listening chairs or sofas, leaving the leather furniture, tables, floor lamps, etc. for another room. If you need a coffee table of sorts, you might consider a larger cushioned ottoman instead.

-IMO
dolfan
109 posts
 
I agree on the $1k fee, yes i know you said $10k. I just used Richard on a 12 x 17 room and the $900 he charged was a very "sound" value. If you want him to be able to charge less do some work for him. Fill out his form YOU get from his web site and list all the material you plan on using. The architect you are already paying should tell you that. Draw out the room and specify a level one job. Show each revision from Rives to your architect for the ok and then send it back to Richard. If you want to save you gotta work!
soundprogression
7 posts
 
Rives Audio knows what it's doing and doesn't have a vested interest in any specific product. If you were to go to ASC, RPG, PMI, Echo Busters and etc there is an inherent conflict between selling a product and selling a design. There are many good products to use but you need a plan first. I use ASC often for instance but I can't use it all the time. I see too many people throw too much money and ineffective material into the room (I'm not referring to ASC).

I would suggest dividing the problem into sections:

Noise control-mostly lower frequencies

Do you need it. If not then don't make the walls exotic but simple sheetrock, studs and fiberglass. You can do it better but simple walls work quite well.

If you do need it put more massive isolation walls on the outside walls. Sound isolation works regardless of which side of the wall your on.

If you must put the isolating stuff on the inside of the room it gets complicated and you need a consultant. The room sill needs to "breath", "be diaphramatic" or damped.

Small rooms have very distinct bass modes. Speaker and seating positions are very important. Bass traps are a very long story I can't share in one response. I'm already long winded.

Sound Performance-mid to high frequncies

Almost every room needs some form of absorption to make the reverberant energy in the room decay but you need to have a broad band absorption and some diffision. Furniture (soft), bookcases (not completly full), some carpet or a rug or two. Fortunately, smaller rooms need absorptin than big ones. There's a formula you can easily find to estimate the decay time (RT60) for your room. It's always wrong for small rooms but it gives you an idea of how much other soft absorptive stuff you need in the room. Just don't put lots of thin big fiberglass of foam in your room. It's the best way to waste your money.

Lower frequencies<~250Hz

You need to know about the rooms behavior either form testing or modeling. Try CARA CAD. It's a great modeling tool and cheap or buy ETF and test the room or hire a consultant to at least take a look at just this part. Bass behavior is a hard subject.

Last word: Good small room consultants are worth every penny and Rives is one of the better ones.

cinematic_systems
282 posts
 
"there is an inherent conflict between selling a product and selling a design."

What? ...a little knowledge can be dangerous Dbk.

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The best and only advice IS to get a good consultant, Bob Hodas or Chris Huston are two of the very best and work for reasonable rates considering there tremendous resumes.

I use Bob Hodas and the people at RPG for all the backup I will ever need to take care of the slightly complicated issues that can occasionally arrive. Clearly taking my own advice at having a relationship with qualified highly experienced people.

The 2nd big hurdle is communicating with your construction contractor to make sure they understand that nothing is arbitrary that the details matter. Look for fear in their eyes, if its there you want to carefully evaluate if these are the guys you want building your room. I am lucky to have a contractor that I have built almost 20 rooms with. The first 5 were very painstaking to work out the specifics of the details and getting the right materials and fixtures. Now we know :) its a little easier.

For the level you imply you wish to achieve you need a real consultant involved with a competent (dealer, acoustician) go between to smooth some minor bumps not just a plan.
stehno
1,453 posts
 
Or you can use a little common sense.

There are no guarantees whatsover that hiring a professional consultant will do a better job than you.

In fact, if your would-be consultant can not demonstrate for you a real system/room combination that s/he designed that absolutely bowls you over with it's sonic presentation across the frequency spectrum, you are probably better off to keep looking for another or perhaps consider taking on this project yourself.

As with some to many things in life, designing a truly superior system and associated room is perhaps more art than science. And "for the level you imply" ultimately, this generally can be accomplished only over a long period of time.

-IMO
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