Minimum Mass for floating floor

Hi. In the moment i start to calculate the floating floor for the recording room of my new studio. Since i`m in the first floor of a nerly modern industry building a can go with concrete, but load/m² is still limited. I kwow about the problemes of reemitting sound from wooden floors, and also the problems of having not enogh mass. My question is in what area the mass of a floating floor must be, to shift the resonant freq in a area where it don`t hurts my acoustic. The material i use for decouple is called sylomer. i will choose the 25mm type w with a best load of 0,0075N/mm² The concrete i will use is about 200N/m² for 1cm thickness I thought about using 4cm thick concrete which gives me load of 800N/m² For this concrete-thickness, a 1m² area needs 11cm² of sylomer to decouple the floor from about 10HZ But what about the resonance of the floor itself? Are there any minimum values for mass? thanks for your help cheers Mika

My first question would be: why do you need to float your floor? Do you have something extremely noisy around that is going to create problems, or do you think that you will be too noisy for your neighbors to accept? Anyway, I don't think you are going about this the right way, to be honest. I think you should first define the resonant frequency that you are aiming for ( I guess you will be shooting for 10 Hz or something like that?), then figure out the mass of your entire studio (not just the floor), THEN figure out what resilient material / air gap / insulation / other things you will need to use in order to get all of the above to work out. I may be wrong, but that's the way I would approach it. I don't think it makes much sense to first decide on the resilient material that you want to use, then try to design the studio construction to match that. That would be kind of like only looking at the tires in order to decide what car you want to buy... - Stuart -

Hi Stuart. Thanks for your reply Yes i need a floating floor, beacause there is some heavy vibrating in the floor, since new people rent the space below the studiospace and carry around some pallets with a forklift all the day. It is not a real noise problem, it is vibrating of the structure which generates a little noise in the recordingroom. My old floor don`t reduce this problem, so i get it out last week. Walls are already build and floated, and there is no vibration on the walls, just on the floor. I won`t get down the walls , since they work pretty good, i just need to put in a new floor, so the mass of the concrete is nearly the only mass i have to calculate. Woodfinish, and one human inside won`t gain the weight that much, and are already in my calculation. Anyway, my intresst goes to another direction: I want to avoid that the energy stored by the floor will be reemitted to the room, which is a common problem with all the woodfloors. For avoid this problem i need mass. But how much??? My floor can handle 2000kg/m² so mass won`t be a problem. It`s more the hight of the floor which sets me limitations. i hope it`s more clear now. I have some problems with describing technical things in english :oops: cheers Mika

Hey Mika. I have two documents that you will need. The first one is an introductory on vibration isolation: THE BASICS OF VIBRATION ISOLATION USING ELASTOMERIC MATERIALS Pay attention to the part on transmissibility . The second is what you may wind up doing instead(using sand and a wood framed deck): 40 kg/m3 and 70kg/m3 rockwool for floating floor Good luck.

Thanks for your reply The Link is very intressting, and i will try to translate it compleatly. :D A wooden floor is not an option for me, since i need a real decoupeld floor, and the sand will shortcut the sylomer pucks in a sandfilled wooddeck. Or did i misunderstud this principal?? :oops: Additional info: I don`t need that much isolation. Maybe about 6db to 10db .I just need to reduce the rumble by the half or so. It`s not as bad as you may think. In a normal E-Git recording you will never hear it, and also in loud Vocal recordings it will not hurt, but i make alot of speechrecordings, and then you can hear/feel it a littlebit. Thnaks for your help cheers Mika

A wooden floor is not an option for me, since i need a real decoupeld floor, and the sand will shortcut the sylomer pucks in a sandfilled wooddeck. Or did i misunderstud this principal??

I think you didn't read through the entire thread, and follow all the links! I suspect that that was the reason why Brien posted the link to that thread: It isn't just about wooden floors, or about sand filled decks. I think you should read it all the way through, form the first post to the last, and also follow all the links off-site...

I don`t need that much isolation. Maybe about 6db to 10db .I just need to reduce the rumble by the half or so. It`s not as bad as you may think.

What is the frequency of that rumble? Is it airborne, or structure-borne? - Stuart -

Hey Stuart It`s you again.... man when do you start your build and stop reading only? i want to see pictures from your studiobuild!!!!!!!!!!!!!!!!!! Yes you are right i don`t follow all the links, but what rod wrote in this thread is what i try to avoid:

It's one thing if you are building an isolated concrete deck - design properly and you'll acheive a 10hz deck assembly - with a weighted attenuation at roughly STC 79. It's another thing to try to acheive any real sort of isolation thru the use of elevated wood decks. You're building a big drum head there - and not only are they difficult to design to get what you want - but they also have a resonant frequency (just like that drum head) where they actually amplify the signal. Concrete does as well - but if the resonant frequency is 10hz - you aren't going to have a problem.

We are talking about structure borne-sound only, which amplify a littlebit of noise in the recordingroom. I don`t messure the freq. until now exactly, but from my experience (ears coupeld to the floor) we talk about 40hz to 80Hz or a littlebit higher. maybe my english is to bad to understad the full game!? cheers mika

yeah, stu, what about your studio. How's that comming together? ;) (*really LOVE to see how you get that concrete baffel wall constructed)

[quote="mika"]Hey Stuart It`s you again.... man when do you start your build and stop reading only? i want to see pictures from your studiobuild!!!!!!!!!!!!!!!!!! My first post. I've been reading for about a year and this was the motivation to register. I too, would like to see pics of your build.

yeah, stu, what about your studio. How's that comming together? ;)

Still working out some final details on the design! HVAC and soffits, and most of all the construction sequence (it's complex!) still need refining. Plus I have an "agreement" with my wife: I get to build the studio without complaint... AFTER I've finished building the new bathroom! So I'm busy building already, but it's the bathroom I'm working on, not the studio... :( Nearly done moving the window, then comes plumbing, electrical, insulation, floor, backer board, ceiling, tiles, fittings... and THEN the studio! ( Sigh! Why did I ever agree to those terms!!!! :!: ) The economic slow-down isn't helping, either: these things cost money to build, and money is tighter than it was when I started out on this project! That won't stop me, of course, but it might slow me down...

(*really LOVE to see how you get that concrete baffel wall constructed)

Yeah, me too!!!! :) But it won't really be an entire "wall": just a couple of large panels, with the speakers poking through. Working on it! (Sorry for the the thread hi-jack! I'll shut up about me now... ) - Stuart -

sigh... I know exactly how that feels. Too many other projects that need attention.

To come back to topic: After all the research i decided to let the math do a pro. Since i have no time to translate all these information and understand it, i think it`s cheaper to let another person do the job. I think also about hire a contractor to do the pouring job, since i never poured a floor. Do you think it`s a waste of money, for just reduce the structure borne sound by about a half? or do you know other less expensive ways to go?? Remember: it is ONLY structure borne sound, and i need only about 6db reduction. cheers Mika

That's a tough question, Mika. (Which is why you asked it, of course!). I'm hoping one of the acoustic experts can answer it. I'm not aware of any other way of dealing with structure-born low-frequency noise, other than to stop it at the source, but that isn't practical in your case. Is it worth it? Well, if it is interfering with your ability to make good recordings, and you make money doing that, then I'd say that yes, it probably is worth it, provided that the cost is reasonable. Do the benefits outweigh the costs? I reckon only you can make that call, since only you know all of the factors, and can weight costs vs. benefits. Tough decision! - Stuart -