School project

Hey, I'm a carpentry student at a local Community College. I have to draw up some blueprints for a project. The plans can be for a house/cottage/building etc. and I thought that as someday I want to build a recording studio onto my house, why not design one right now? Currently, I'm working on the foundation. I may have missed them but I can find very few posts about laying a foundation for a studio. The studio I'm designing as of now is going to be 20'x22', not too big. I've been doing a lot of research on the layout of the interior. But the foundation still eludes me. I'm looking for general knowledge about soundproofing from the ground up, particularly about concrete. Will the footings affect the sound in any way, i.e. is there a particular way to make a footing better for a studio than a normal footing would be? For the slab, is there a particular thickness that works best? is it the thicker the better? Are there any soundproofing materials which should go underneath the slab to absorb ground noise? On top? And lastly, in an idea situation, would the walls be made of concrete? Or are there better materials to soundproof the walls with? Sorry if this has been covered before but I have had trouble finding it. Thanks!

Tim, First, while I applaud your want to move from the one area that you are barely familiar (house design) with into another area that you are not familiar (acoustic design) with :) I would suggest a slow move forward....but fast is good as long as the information is accurate, and that is an important word...accurate, followed by tried and proven. "For the slab, is there a particular thickness that works best? is it the thicker the better?" The TL (transmission loss) of the floor does depend on thickness. But there are deciding factors that can determine the actual TL of an Earth damped slab. The first is that it is always recommended that the Earth be dirt, this is what helps to damp the concrete to stop the flexing and when flexing does happen it has the mass of the Earth below it to absorb it (vibration) and reduce it. Depending on where you live, this can be a blessing or a curse. If you poor concrete on top of backfill properly prepared for a house then you can minimize the sound transference from the Earth damped slab into the Structure. This is important to remember. The ground can be involved with how the concrete slab interacts with the structure and can modify the TL of the overall build...flanking is the word I am referring to which will raise the TL, at your level you may be looking at STC (sound transmission class) but this has to do with what the human ear can hear and has nothing to do with what musical instruments (and some human voices) can develop in which there are low frequencies involved that "excite" a hard boundary and cause it to flex at certain frequencies, creating an acoustic "hole" in the boundary. So, let's think about if you live in an area that has a rock substrate. Pouring concrete on top of a hard interconnected surface like, say, granite in Tennessee or where Marble is located like any number of a dozen places world wide, Italy, China, Turkey Belgium, France, Great Britain, Spain, India and many parts of the USA. What you essentially do is bond a hard surface to another hard surface. Now this might seem like a good idea at first site, but there are reasons why you do not want to do this. Roads and the trucks that travel roads, cars and the roads that cars travel on produce low vibration in these environments. The LF (low frequency) moves right through the ground from the wheels of the vehicle directly into the concrete of the room. I have personally seen tall brick walls built in an effort to address this issue, me just shaking my head, the thinking on the engineers part was that it is air borne and could be mitigated by the inclusion of a massive boundary to impede this travel of sound. They were looking at the wrong area, but I am not "papered" so my vote didn't count so to speak. "Are there any soundproofing materials which should go underneath the slab to absorb ground noise?" Sand is the best way to bolster the ability of a concrete slab, no matter what the geological environment is and sometimes in spite of it. Sand has mass and is dense but it does a beautiful thing in that it is flexible. One of the things we look for is MASS and flexibility. This is why you will see MLV (mass loaded vinyl) getting so much attention from neophytes. MLV is over-priced and under-performs so forget I mentioned it. But mass and flexibility is key. Why you may ask? Mass controls the ability of stopping sound and flexibility damps the vibrations there by attenuating the sound. These are hard things to achieve in any build. Ideally you would build the structure out of sand...but how do you support it and how do you walk on it and how do you keep it over your head without it falling, right? How could you pay for that? "And lastly, in an idea situation, would the walls be made of concrete?" Yes, in an ideal situation, money is no object that is they way to go. BUT, you are wanting to design houses and structures and you will always be burdened by a "budget". Always. There will be concessions made there will be modifications in the build as a direct result of how much money there is and how close can you get to spending that amount and ONLY that amount.

Hey thanks! That helps a lot! I hear ya about the budget. I'm going to design it as if money isn't a problem. Once I am ready to build it( not for a few years at least) I'll be able to make a better estimate of how much I have to spend on it and go from there.

I'm impressed! I'm pretty sure that's the longest, clearest post ever from Brien! :yahoo: Very nicely explained, too. Timothy, Brien is usually a man of few words, so the fact that you got him to write half a page of detailed, clear, concise information is pretty amazing! How did you do that? :) (Just pulling your leg, Brien... :) ) About the only thing I can add to what Brien said, is that you might want to buy the book "Home Recording Studio: Build it Like the Pros", by Rod Gervais. It covers a lot of the types of details you will need to know for the actual building structure design. I'd also suggest "Master Handbook of Acoustics" by F. Alton Everest (that's sort of the Bible for acoustics), which is a great book for learning about the basics of acoustics, isolation, how sound works, etc. - Stuart -

I said I was trying to be better...this is my "olive branch". :0 I got it in me, but refuse to let it out?

Haha nice! You give good clear answers so you really should continue!

Nothing much to say Tim, your a student I can not take the test for you or do the work for you. What I did was explain something that is not easily grasped nor is it available in books that you have on your shelf. It comes from being involved in this business, for me, carpentry/acoustics. Design comes from the understanding of acoustics and the build will be put in the hands of the trades, but your job is to understand in some part all of what it is that the trades need to achieve in order to meet a specific isolation or interior treatment goal. If that sounds like I am asking a lot of you, it is exactly what it is you are going to have to do in order to proceed to the end of a project. I would ask you to spend time on the word "decouple" as this can mean many things and with the aid of the Internet will come at you from many angles, some worth the research and others not. In order to get the best understanding of what it is that "decouple" means, you have to sift thru the ashes of many a burned idea in order to locate a consistent conceptual notion that proves itself to be a perfect fit in any environment for any aspect of the build and lends itself to any geographical location. For instance. If money were no object then the best slab you can produce for a well isolated environment will be one that can isolate down to 10Hz and is "decoupled" from the exterior of the structure. These are things you have to study, they will not pop up on a forum. Alton Everest author of "Master handbook of Acoustics" is the hand book to go to for clear concise information in this respect. But also you can not dismiss "Noise Control for Engineers" Author Harold Lord. An online source of information that we commonly refer others to is the "National Research Council Canada" website: http://www.nrc-cnrc.gc.ca/eng/index.html You can find any answer to any question you want to ask once you know how to ask the question. Good luck with your studies my friend.