percussion suppresion

I don't think you can apply it, but...

2.5" x 4" x 4" blocks of rock maple turned on end, floated in 1" of New Jersey yellow clay (similar to baseball infield "dirt") on top of a 6" concrete slab. It will absolutely work. Now, as for anything remotely practical, well...

owww

LOL!!!

2.5" x 4" x 4" blocks of rock maple turned on end,

sounds like bowling alley material.

You have two courses of action.

1. Raise the floor upstairs so that it "floats over the original floor.

2. Lower the ceiling downstairs so that it floats under the original ceiling.

A third option is to offer special dining rates to the deaf!

In cases 1 and 2 you are acoustically isolating the two rooms with barriers that will not interact with each other. However, the space between the two must be filled with a sound absorbent material like fiberglass to dampen higher frequencies.

Right now when sound strikes the upstairs floor it will vibrate like a speaker cone. Since the ceiling downstairs is mechanically coupled to the upstairs floor via the floor joists, the ceiling simply is the back side of that virtual speaker cone.

The trick is to decouple the two mechanically and add sound deadening material between them to absorb any sound that echoes between them. If you don't it will be like a double sides drum and will not get the desired results.

You will probably need an architect to do this since it is a public building and will no doubt require a building permit. I would recommend finding an architect that specializes in acoustics and sound stages or has access to someone that specializes in this field.

I have worked on a few recording studios that employ these techniques (and a few others) and the amount of sound dampening between rooms will amaze you. Done right the downstairs may not even be aware of the upstairs!

thank you for your replies

this is a case of no budget and lots of love for the art form

i know about sound isolation

the sand box idea is interesting

i was hoping i could find something like a hydraulic set of feet that perhaps absorbs

the blow.or at least something that could minimize the percussion transfer to the

floor.

Here's a better solution. Add a third floor so that dancers, etc, are isolated from first floor by an entire floor. LARGE air gap = sound suppression. Of course, cost may be a slight issue.

Instead of raising the floor. Place insulating barrier on the floor you have and place another floor above it. Check to be sure the stage can handle the additional weight.

I have no Idea if this would work. Could you suspend the small stage from the ceiling as it would float above the floor and not transmit vibration to the room below.

Good idea BigEdm.

How about this. From a practical standpoint, we have an upstairs (dancers) and a downstairs (diners). Now, how shall we separate them? First by distance (not the best solution in this situation), then by soundproofing- foam, alternate rafter separation, etc,.) not really the best idea either. So, what's left? We could use your idea and suspend the stage by cables, etc. (not, at all, practical). Or we could use the idea I suggested earlier by separating the dancers from the diners by an intervening floor (lots of sound absorbing airspace). Now, if there's not a third floor to work with, do we have a basement for the a) diners, or b) for the dancers?

IMHO your situation is best resolved by distance.

-John

How about diners on second floor, dancers on the first floor.

Ed

ok

thanks guys

all your ideas would work

so far

after comment # 1

i recalled a friend who told me they made a huge sandbox to prevent vibration

while shooting holograms

so that idea , in conjunction with a dead weight and a floating stage

uh huh

im still thinking

although im going to go back to my original thought

is there small hydraulic shock absorbers that can also be apllied like feet under the

stage ?????????

and . . . no i cannot go downstairs

it is the upstairs that is being offered as a venue if we can figure out how to

minimize the sound that would disturb the people directly bellow

think , someone hammering a nail into the floor directly over your head

its not so much the high end sound were concerned with

its just the "direct" percussion sound directly under the stage area downstairs

thanks

Here is my favorite vibration isolation product:

http://www.fabreeka.de/index.htm

You may well be able to design a raised dance floor that is isolated from the floor of the second story. The problem is you have two modes of coupling of the dance energy. The first is the direct vibration, the feet stomp the floor, the floor vibrates, the ceiling below vibrates, and the diners are bothered. This can be helped with isolation.

The second energy coupling mechanism is acoustic. The feet stomp the impact generates sound, the sound couples into the walls, floors, and ceiling, piping and ducting of the second floor, which transmits that energy to the first floor. You will not be able to solve that with isolation. You only solve that by putting tennis shoes on the dancers which defeats the purpos of flamenco...

I really don't see this problem being solved without some serious engineering modifications to the building. I would suggest that even if you moved the diners upstairs and the dancers down stairs that it would still be a problem.

The only solution I am afraid is to stop the dancing, or stop the dining, or find diners that appriciate the dancing...

Where are you located? I would be interested in having a look to see if I can dream up a solution to the problem, but it will be pretty hard to do via the interenet. I also may be able to refer you to someone in your area. The noise and vibration field is pretty small and tight knit.

toronto canada

thanks for offering

ok so far im thinking

sound blanket

sand bags around the bottom perimiter , to elevate the stage and deaden the sound

sound blanket on stage

sheets of half inch ply double laminated together the size of the stage

floating on top of the sound blanket

mike the footwork

it kind of incorporates everything suggested exept suspension

were not too concerned with the building vibration

there is piped music downstairs and the loud talking helps

( ohh. .... any knowledge of a good surface that will suvive this onslought of

footwork?? generally people just use ply or whats available, so maybe theres a

product out there that is perfectly suited to this craft)

thanks guys

i wont get to try this project for at least about a month so this is really

helping to hone down my approach

By the way, you need to be concerned with building vibration, since any part of the building that vibrates will cause air to move, and that is sound...

Are you open for dinner? I am always looking for somewhere new to have dinner...

hi steve

its not my restarauaunt

but if you let me know when you would like to try tapas etc;

i will set up a table

just leave me your info

eartmanindia@yahoo.com

My business in Toronto got moved to the week of April 21st...

I still hope to stop by for dinner.

Guest,

If you can have the dancing area a few inches above the building's floor surface, try either of these two ideas. Both of them use the approach of isolating the dancing surface from the building's actual floor to minimize conducted noise and loose insulation to minimize air transmission of noise.

1. Build a fairly stiff raised framework with 2x4's on 24" centers and a second layer of 2x4's laying flat-ways, on 24" centers the cross-wise direction. Support the lower 2x4's on leaf springs spaced on 4-foot centers. Use springs that are rigid enough to only allow about 1/4" of deflection when loaded with 600#. The ends of the leaf springs would be attached to the actual floor surface with rubber vibration isolation pads under them. Edge the raised framework with lumber and a flexible fabric or plastic which would dress its exposed side. Cover the building's floor surface with fiberglass insulation or 2-3 inches of loosely blown in cellulose fiber insulation. Finish the top of the raised floor framework with 3/4" tongue & groove plywood and a finish layer of thin engineered wood flooring so the dancers have a good surface for their feet. This will give you a solid surface only about 7" above the building's floor and provide very good isolation of the mid to lower frequency sounds caused by the stamping of the feet. It will also be stable and free of unwanted vibration. If there is too much oscillation of the dance surface, you could add shock absorbers.

2. Do the same as above, but instead of using leaf springs use inner tubes in the 24" x 24" square areas. If they are not thick enough to keep the dancing surface floating above the building floor, you could add 1" or 2" thick pads of fire resistant foam under the inner tubes. This will probably give greater sound isolation than the method above. It will have more motion both vertically and side-to-side. If the side-to-side motion is too great, you might have to add guides or cables to help.

--John M.

Sounds a little too elaborate for me. I sincerely believe if Yanis will just build a simple sandbox the size of the stage (slightly larger) with retaining walls to keep the sand from moving away under the weight of dead load + live load (anticipated dancers). Make the sand, perhaps, 12 inches or so thick.

Some modifications may be required in order to make it practical however. I go with KISS in this case.

I think it may very well work, and, the expense will be minimal.

-John

Johnjohn,

Perhaps it is more elaborate, but I am concerned with the practical areas of weight and elevation. The 12 inches of sand with dancers on top probably exceeds the allowable dead load and live load limits of the structure.

--JMM

Good point. But I think maybe if a steel I-beam frame were used for the sandbox, it could be extended out to load bearing structures (walls, etc.) to distribute the load evenly. I guess what I'm saying is to support the sandbox on either steel I-beams or even engineered lumber joists. The main point is that sand is probably the best sound dampening material for this application. Of course some specific engineering calculations would certainly be in order, etc. Think back to spring break when you danced on the pavillion on the beach. Maybe it wasn't a sound problem because

a) Everyone was loaded.

b) Everyone was barefoot.

c) Anyone within earshot didn't give a damn anyway.

JMHO anyway.

I'll be in Toronto the week of April 7. If you wish I would be happy to have a look at it. Drop me a private message by clicking on my screen name a selecting message if you wish...

hey steve

im right downtown

bathurst and queen

the Segovia Restaurant is at young and wellesley

im at 416 504 1642

re the sand

i was considering making a channel around the perimiter of the stage

then i place sandbags ,used in film, in the corners and every two feet

(these are the sandbags with the industrial strength ruberiized coating )

butttttt ...... now im beginning to like the rubber tube idea in terms of weight and

soundproofiness

my unsureness would be in the stabillity and level surface