Hey people,

I was in home depot (reno depot) today and i saw on the stands they had this rubber matting for outside on your steps its made from recycled tires.

I was wondering if anybody ever thought of using this to float the floor for iso booth.
The material is about 1/2" thick and 9" x 35". If it was cut to fit under floor joist would it be springy enough or too hard compared to things like u-boat or other types of material used to float joist.

Just a thought.

Thats what it looks like
Shop Secure Step Black Rectangular Stair Tread Mat (Common: 9-in x 35-in; Actual: 9-in x 35-in) at Lowes.com

Skalz,

I'm sure we can find a useful purpose for that in a studio, however it would have to be tested in each situation. There is no way to know what sort of resilience you might get from that.

It will probably work about the same as U-Boats.... 'okay' for impact noise, but otherwise useless for 'floating a floor'.

As you might guess, my opinion of U-Boats is pretty low.

To 'Float' a floor, you must have complete specifications on the 'spring' material. Otherwise, you'll be opening a box of chocolates... you know what Forest Gump would say, right?
The minimum specification requirements would be:
a. Durometer
b. Max Static Load
c. Optimum Dynamic Load
d. Dynamic Stiffness

The specs above are only available for materials manufactured consistently and tested for these specs.

'In a Pinch', (in countries where tested products are not available), we have used resilient rubber mats and similar, but only after we have tested them individually for conformance to the use. These are only ever used for Impact Isolation or non-critical vibration isolation.

Hope this helps.

Cheers,
John

John nailed it in his answer above........

Might they perform exactly like the U-boats - they sure might - but that leaves us in exactly the same condition in either case - which is that the outcome cannot be predicted.

Rod

Floating floors: how to avoid common mistakes. in The Acoustics Forum Forum

Except for the statement:
"You cannot float properly on:
......
- Any sort of rubber
...."

We've successfully floated many studios on rubber. Rubber is fine as long as it is tested and specified for that particular use. Rubber is a good isolator down to about 8 - 10 Hz. - If you need to go lower, you need a steel spring. But you probably need rubber WITH the spring... this is because a spring, by itself, will transmit higher frequencies - flanking THROUGH the spring.

To be specific about the frequency where the resonant structure begins to actually 'isolate', it is = square root of 2 times the resonance of the structure. - Therefore, to be exacting (splitting the hair, so to speak) - to begin isolation at 20 Hz, you need a MAXIMUM isolation structure resonance of 14.1 Hz. Rubber does that perfectly fine. - But remember that's not just ANY rubber. ok?

As I said before, the rubber in question has to be manufactured and tested for this use.

Cheers,
John

Also note: I do not Sell or Profit by ANY of the products that I might specify for any particular job, therefore you can trust that my recommendations are without bias due to any conflict of interest.

Our experience is that no rubber will go to these frequencies. Measurements between Sylomer and 'natural engineered rubber' optimized for the task gave the Sylomer up to a 9dB (!) advantage in the low frequencies (under ca. 60Hz) - since rubber just can't go as low (natural frequency). "Rubber" is also a lot more sensitive to temperature changes etc.

REGUPOL etc are better than "rubber" but still far away from Sylomer.

Spring + Sylomer will allow very low frequency floating under 5Hz and indeed avoid transmission of HF and MF.

I do work with a company selling these things (AMC). We work with them because they manufacture top systems.

Thomas,

Surely you have heard of Mason Industries, Vibro-Acoustics, Kinetics, etc.?
We've also used AMC products and are very familiar with them. I think Mason would be the first choice or go-to product as they have always been more robust and have a proven track record.

It's not too difficult to get a quality rubber isolator to work down to 5 Hz with the proper load. Just about ANY spring (1" or 25 mm) will offer a resonance at 5 Hz. A 2" deflection spring will give you 3 Hz, 3" deflection - 2.5 Hz, and 4" deflection will work at 2.2.

But for Music Studio Isolation, like you said in the post quoted, a 10 Hz goal is ideal. Going lower when you don't need the isolation can be like throwing money down a lava tube.

We've spec'd designs for inertia bases for Coordinate Measuring Machines at an automotive stamping facility. After site testing, it was determined that the vibration isolation required was met with a heavy inertia base mounted on Mason EAFM rubber.
Works fine. (And we saved the company thousands of dollars.)

If you'd like more information, send me an email.

Cheers,
John

John, I don't really need more info on this, but thank you.

We have used products from all main companies in the field, Some we will happily use again, some we won't.

I would not say 10Hz is an ideal goal, it's the bare minimum benchmark (and we always go for 7Hz or lower in practice) and in a situation where you also know the value for each point (or stripe) load exactly.

Which as you surely know is not realistic as floors are not rotating engines where you can determine easily the static load on each suspension and verify it empirically. Hence the need to aim at lower natural frequencies and systematically over-engineer a floor.

Especially with building structures, with deviations piling up such as real-life amount of concrete on the deck vs calculated/theoretical one for example - although there are ways to preemptively reduce a bit the impact of such cumulative deviations.

I'm all for saving thousands of Dollars - but in my experience, running the numbers seriously and mounting the structures rigorously, there was always a substantial gap between the two. So I picked the one that performed best.

Most vibration sensitive factories, such as micro-processor engraving facilites, use active pneumatic systems these days.

Rubber works very well for some applications, often where the natural frequency can be over 10Hz, but my experience is that there are better performing solutions these days for the exact same price.

We all have our little habits I guess - as long as the results are there and steady from one project to another, it doesn't matter what brand and type you use.

Have a nice day,

Thanks guys for your replies.