just starting ?? about foam for acoustics

[philcan]

I'm just starting to convert my unfinished basment into a small home studio. No a ton of gear just a 8track digital recorder a sm57 sm58 and a condenser mic for vocals ( I have a mixer and some outboard stuff but the 8track seems to do better than using the gear).

The room is pretty much a square. It has cement walls and floor with bare rafters for a celing Demensions are probably 20 X 20. I have a carpet that is about 12x12 in the center of the room. I pretty much will use half the room (no plans right now to put up a dividing wall. The non used side of the room has the washing machine dryer & furnace (great sources of noise that I will have to deal with later I'm just starting.) I checked out some books but there is really nothing middle of the road they all seem gearded for the person spending 100,000 on a studio or the person who is spending 0 and hangs bed sheets to deaden sound.

I basically want to do 2 things

1. cut down on the sound reflections that the cement walls are so great at doing. I think this would lead to better recordings.

2. try to isolate the sounds from the rest of the house IE kids and dogs plyaing ( sounds more like rioting) upstairs and keep them from showing up when I try to do vocal tracks.

My original plan for the walls was to buy about 100 acoustic foam tiles ( cost about 180.00 covers about 28 sq feet) and glue them direct;y to the wall. Rather than waste some money and do something stupid I decided to ask for some advicxe first.

I'm not sure what to do about the celing yet?

Any advice will be appreciated.

THANK YOU

 

[c7sus]

Lots of good info here:

http://johnlsayers.com/index.html

Kids making too much noise is why they came up with mom's and matinee shows at movie theatres.

Cheapest solution to that problem.

You were right to ditch the acoustic tile solution. That's not gonna help matters very much.

Acoustic foam looks on the surface that it might be helpful, but the more you read and learn you find out all it's really good for is sucking all the high-end out of your room. Applied directly to cement walls I doubt you would get any really noticable improvement.

How much do you have for a budget?

A low-cost solution might be to go ahead and build a wall or two, say in a corner of the basement. Then you only have 2 cement surfaces to deal with, and a smaller area overhead to fix as well.

 

[philcan]

thans and a few more ??

Thanks for the site. I'm checking it out now. I guess i may have a couple hundred to treat the walls and floor I may just spend a little more and refinish the basement. I may have to do a bathroom upstairs first ( my wife has a little to say about it but she benefits from a remodled basement a little too. I guess the best question is.

What should I do first walls floors celing?

 

[mixsit]

Hey, just an F. Alton Everest fan DI-Yourselfer here, but fiberglass, cloth and ply wood's cheaper than foam. Check out some of his books as well. Lots of good info and options.

You're going to want to break up the parallel bounces between the walls and floor/ceiling no matter what. Maybe try some partial coverage absorption first.
The ceiling only makes a lot of noise maybe sometimes? Isolation from the noise above might be the tough one. (Lots more mass.
I did some regular fiberglass panels, 3 and 6" depths on 1/4 or 1/2" ply, some mounted, some stand-alones to move around. 3" gets you down to around a few hundred Hz but the freestanding ply board should also help a bit on the lower end as well as providing some flexable isolation options.
Hope that helps some.
Wayne

 

[Ethan Winer]

Phil,

You got good advice, especially to avoid covering your walls entirely with foam. The best bang for the buck is rigid fiberglass, and you need a lot of it in the room corners as well as in selected spots on the walls and ceiling. Have a look at the Acoustics FAQ, second in the list on my Articles page:

www.ethanwiner.com/articles.html

--Ethan

 

[mixsit]

Ethan, I keep seeing ref to ridged fiber glass, but Owen's specs show the low density (much cheaper) stuff being as good, and in parts of the spectrum better than the boards.
Except for ease of mounting, why ridged?
Wayne

 

[alphadelta80]

Aint that the truth

You guys could'nt be more right. I made the mistake of covering my entire vocal booth (all walls and the ceiling) with aurilex foam pads. The result is vocals with no high end. The vocals sound like I'm singing through a balloon or a pillow or something. It sucks. Now I'm kicking myself trying to figure out a way to make my vocals sound more natural while still maintaining the same leel of sound Isolation from the rest of the house. Any suggestions guys? I will say this, Save your money. Don't be a dope like me and spend $16 a piece for a bunck of 2x4 foam pads.

 

[Ethan Winer]

Wayne,

> Owen's specs show the low density (much cheaper) stuff being as good <

The short explanation is the Owens-Corning data was taken with the panels laying flat on the floor. But the correct way to mount rigid fiberglass is across corners and spaced away from the walls. When you mount it like that the denser rigid types work much better, and the published data becomes meaningless.

--Ethan

 

[mixsit]

Thanks Ethan. I figured you might be looking at that kind of mounting. They have their 'E' mount specs which is with a 16" gap.
Wayne

 

[Ethan Winer]

Wayne,

> They have their 'E' mount specs which is with a 16" gap. <

Do you have data for the various types of rigid fiberglass with E mounting? I have only incomplete data. Anything you can email me or give a link to will be most appreciated.

--Ethan

 

[mixsit]

Found these at the Owens site that refer to 'E-405', but it's very limited info. I couldn't even find where ever it was that said E was 16".

http://owenscorning.com/around/sound/commercial_acoustics/pdf/SoundAttenuationBatt.PDF

http://owenscorning.com/comminsul/documents/Insulation Specification Technical Data Guide.pdf

Mostly I've just combined the sketchy info from Owens with the (much more informative charts in Everest's 'Sound Studio on a Budget'. He shows freq. vs depth, freq. vs density and freq. vs air space (only 3" though). (His sources are Owens by the way.)
But even if Owen's E' is 16", it still seems that a simple 4" of fiberglass kills anything thinner or denser regardless.
But again, all these charts stop, and the coefficients drop like a rock, at 125hz (with the exception of 4" of fiberglass which comes in at .8 @ 125hz).
None of this stuff seems to be aimed at the bottom octaves though. Would I be correct then to assume then that options for the 40-100 hz range come down to either very large surfaces of diaphragm action or very deep traps? (or open windows and doors. (The DIY'r in me comes out again.
Wayne

 

[Ethan Winer]

Wayne,

> Found these at the Owens site that refer to 'E-405' <

Thanks. 405 is the number of millimeters of air gap, but the only place I saw E-405 referenced was for the fluffy fiberglass batts. There's no need for them to define E-405, and you'll sometimes see data where another gap size was used.

> None of this stuff seems to be aimed at the bottom octaves <

It's mainly that they don't spec it lower. Rigid fiberglass does absorb lower than 125 Hz, and there are techniques - air gaps, adding membranes - to increase performance at lower frequencies.

--Ethan