Room Accoustics and Soundproofing

[HiSix]

Anyone here involved in building soundproof and accoustic spaces in homes DIY projects?

I got samples of magnesiacore which looks like great material to kill sound. The website is www.magnesiacore.com and I want to see what's the best material to make walls, floors and ceilings.

[martin clark]

It's rarely the material choice itself so much as the way you put together the whole package that governs the isolation you can achieve between spaces. The knid of product you've linked to looks useful for certain properties, but it's not necessary to achieving great isolation. I'm an architect, and do get to specify this sort of thing regularly. Once you start aiming much over 40dB Rw then it's easy to destroy the performance by careless construction - it all goes to pot if you end up with unintended services penetrations, poor sealing or offcuts bridging the cavity(ies). On the other hand - it's quite straightforward to achieve 65dB+ of isolation with regular sheetrock and just a little care.

That comes from careful design and even more importantly, careful contruction. All major plasterboard/sheetrock suppliers have products optimised for acoustic control (ie increased density) or you can just add extra mass via more layers of regular sheetrock, but for high performance the use of resilient hangars, staggered/double stud consturction and internal damping (mineral fibre to damp the interstitial space(s) becomes much more critical than the board choice.

Have a good read of a book like F. Alton Everest's 'Master Handbook of Acoustics'. It's clearly and concisely written, and buying a copy will be a lot cheaper than making uninformed construction choices.

HTH!

[Ron E]

I'm with martin, get yourself a studio construction handbook - F Alton Everest has written many. Define your goals and research how to achieve them. You can make an extremely soundproof wall with staggered studs, resilient channel, etc....

[FastEddy]

Often the best sound insulation is also the best temperature insulation ... if your walls are not already insulated for heat/cold, do that first = saves $$ bucks on gas / electric bills, too. After your walls & ceiling are thermally insulated, then add the acoustic sound insulation as required.

Martin Clark: " ... It's rarely the material choice itself so much as the way you put together the whole package that governs the isolation you can achieve between spaces. ... you can just add extra mass via more layers of regular sheetrock, but for high performance the use of resilient hangars, staggered/double stud consturction and internal damping (mineral fibre to damp the interstitial space(s) becomes much more critical than the board choice. ..."

What he said. ... Room positioning of the speakers is important initially as well. A decent gap between speakers and walls can do wonders for any neighbors' complaints. Carpets on the floors help too as do curtins on the windows.

[HiSix]

Thanks guys. Great info.

I got all these points and the key points from all what I can gather are isolation and density to absorb sound. The density is what attracted me to magnesiacore for the wall, ceiling and floor. Then "green glue" (accoustic glue/caulk) would be used to provide isolation between the much denser magnesiacore which I would apply over the existing drywall (walls and celing) and also over the concrete floor. Kind of a creating a floating dense mass over the green glue as the isolation. Makingover just the interior of the existing room.

I think this should work for the extisting room in the basement without building the room over from scratch. Making it more soundproof. (DIY project and I don't want to make too much of a mess or get trades involved or tear any thing down to rebuild walls and ceilings)

I have to work on the door and vent openings somehow.

[FastEddy]

One thing you might try before you make anything permanent ... if you have access to them:

Those portable, temproary walls that make cubicles in office space, usually cheap when used and make for good adjustable sound deadening panels ... move 'em around until you get the room response you really like, then go to work with the hammer and nails ... a cheap trick often used to "tune up" small auditoriums, prior to the installation of the final mix ...

[martin clark]

Just a quick note that acoustic behaviour inside a room, and the isolation between that room and the bounding spaces are two entirely different problems!

HiSix -About doors - presumably you want to improve the isolation the door offers. Two keys to achieving this: mass, and lip seals. Domestic internal doors are often little more than two ply/masonite skins over corrugated cardboard core - useless for your purposes, they only offer Rw of 18-20dB. Substituting a solid-core timber door will help, and one economical way we spec commercially is to make all doors out of fire-door blanks (since these have solid chipboard or flaxboard cores); these are little more expensive than a 'regular' doorleaf, but will give you Rw 30-32dB when used with lip seals (brush, batwing or wiper type). 44mm (1-7/8ths) leaf thickness is good, 54mm (2-1/8") is better. Ensure the door is hung with minimal clearances all around, too.

This is certainly cheaper than going to a supplier and asking for an 'acoustic' door - which will be the same damn thing with a much increased price tag! If you really want/need 40dB+ performance though you must expect to pay for it...

[HiSix]

For the door, (since it luckally opens into the room) I plan to reinforce the hinges (say a piano hinge) and apply a sheet of magnesiacore over the existing door that is a couple of inches larger than the door. This will give me a good lip to work with that I can apply a foam gasket to seal when the door closes.

I will use the green glue and some threw bolts with rubber washers to bolt the panel to the existing light weight door. I think this will work to add mass and isolation to the door opening and create a seal.

[martin clark]

That sort of thing is a good start, and easy DIY. No need for Piano hinge though, just add a third regular hinge about 2/3rds the way up the door if you're concerned about weight.

There's an easy-to-read article on the importance of the seal here:
http://www.gai.org.uk/pdfs/TechUpdt.5.web.pdf

(this is UK-based, but the principles are the same the world over)

[marekst]

I agree that Everest’s book is a must. I am not sure what yours magnesiacore is but I do not like high density or hard material for its sound. I have concrete floor in my room because I couldn’t do suspended wood. Halve of my floor is covered with carpet and it is OK. But if you cover walls and ceiling with hard boards you will create a bunker. There are different opinions on walls: some like it light and flexible for maximum bass absorption, I have 5/8 gypsum boards on rather stiff frame (2x6 16” on center) for bass energy preservation. I treated room corners to absorb standing bass waves only. Gypsum boards, gypsum stucco or wood that’s not too hard is my choice for surface material. Any hard surface like glass, ceramic tiles, pergo, oak etc should be avoided. Sound proofing is another matter but adding little mass will not solve the problem. In my opinion, if you really need sound insulation, double studs walls (and ceiling) of some kind is the only way to go. All my walls are outside walls. From heavy but single stud walls I have about 45 dB attenuation; I do not need more as I live on a quiet street. I could hear birds and frogs through sealed single solid core door - a second solid core door was necessary to drop the noise level below 20 dB. One of my doors is a garage door but it is framed like a wall and triple sealed, it is hung on industrial hinges. My window and AC has a solid core sealed shutter also. The ceiling plaster boards are hanging on 2x8s that are not connected to the roof. Room shape, dimensions and acoustic treatment is another chapter.
http://gallery.audioasylum.com/cgi/v...21150&session=
I am not an acoustical engineer, my room is totally DIY - when building it I was more concerned about sound than looks. The room and speakers are the most important part of audio system. By doing it yourself you can go beyond commercial solutions.
Marek