Any accoustics experts?

[Kyle Kraft]

I'm looking for ideas to control the reverberating sound issues in my shop. I have concrete floors, sheetrock walls, and a steel ceiling. The shop noise bounces off every hard surface and is somewhat annoying. A neighbor gave me two really nice room-sized carpet remnants and I was thinking of "upholstering" a frame with it and hanging them like pictures on the wall to absorb some of the sound.

Any ideas from the experienced in this area is welcome:)

[Chuck Wintle]

You could always try some acoustic panels used for false ceilings. Maybe put some on the walls too to absorb the sound and keep it from reflecting.:)

[Jamie Buxton]

Carpet will reduce the higher-frequency sound reflections, and free is a good price. There are also products specificially intended to reduce sound reflections, but treating a whole shop may get expensive. A different approach would be to wear earplugs or earmuffs: thery're much less expensive, and they work better.

[David G Baker]

Kyle,
I am no expert but have worked in the broadcast business for years. The carpet will help a lot. Foam egg carton pads are what we used in the audio booths, they were glued to every surface except the floor and the floor had a heavy mat on it. Real egg cartons, believe it or not will help some.
My pole barn has metal siding with one inch double foil foam board insulation under it, composition roof, 14 inches of blown in insulation in the attic and an insulated metal roll up door. The door faces the street that is approximately 200 feet away. Every vehicle that drives by sounds like it is coming up my drive way. There is a small lake about 1/2 mile away that has a lot of jet skis on it in warm weather. They are also driving up my drive way.
The metal ceiling may be a portion of you sound bounce.
If you have the room and can stand it, try the carpet hanging method. Try blue foam board as a barrier. Portable folding screens made from 1/2 inch plywood coated with soft foam may work.
If you are the only one bothered by the sound they do make electronic sound cancellation devices.
I probably didn't help much but maybe gave you a few things to think about.

[Al Willits]

Acoustic absorbstion pannels can be made out of 2" or 4" of 703 fiberglass with a cloth covering, if your interested I'll go look up the plans for them, fairly easy to make.
And ya can also use them in your HT room if ya want...:)

Al

[Chris Friesen]

There are commercial sound absorbant panels. You'd also gain something by "floating" the sheetrock on resiliant z-channel designed for the purpose, and putting insulation in behind it.

The cheapest option is a good set of earmuffs.

[Rick Gooden]

Kyle,

I design and install AV systems for churches and fight this all the time. There really isn't a cheap fix. For a primer on acoustics go to http://auralex.com/acoustics_introduction/acoustics_introduction.asp. I believe this will enlighten you on what is involved.

Rick

[Kyle Kraft]

Thanks for all the various ideas!! I'll probably start with the low dough solutions, and work my way up. I will post an update in the future with the results.

I appreciate all the input!

[Tyler Howell]

Insullating and fiber board on the ceiling will make a world of difference.

[Lee DeRaud]

Insullating and fiber board on the ceiling will make a world of difference.What he said: I suspect that steel ceiling is most of your problem.

The carpet on the walls would certainly help too, but at least in my shop, there's just no way I could give up that much storage space.

[Al Willits]

An add to from what Lee and Tyler said, here's a couple of options.
The Ceiling Max is what I'm gonna use in the basement HT room, only takes about a inch or two of space.
It will take the basic acoustic tiles you see in office building and give some sound absorption

http://www.acpideas.com/index.cfm?XlinkID=13

These can be used with the ceiling max or suspended ceiling, bit pricey but work well

http://www.sweetwater.com/store/detail/MetroDiff/

Al

[Kyle Kraft]

Wall space is handy in my shop also, but I have 12' ceilings, and I was going to put the carpet "pictures" up above the 8' level. The wall space near the ceiling is only used, in my case, for vintage corn signs, a clock, banners, etc.

I agree, the sheet steel ceiling doesn't help with the sound issues, but it sure was a breeze to install....and no mud, tape, or paint!!!!

[Cliff Rohrabacher]

Spray insulation Foam on the Ceiling.

That'll kill a lot of high frequency bounce back
High Freq is the part of your hearing that will go first as you age, Human ears are susceptible to damage from ambient High Freq noise, and it's probably a good idea to take some affirmative step to protect your hearing and insulate the ceiling.

[Dave Fifield]

You can make your own sound absorber panels much cheaper than buying Auralex etc. and they will be much more effective too.

For my music studio I made a bunch of just such panels using 48" x 24" x 4" panels of dense fiberglass inside a simple wooden frame, covered with old speaker cloth to make them look good. These hang in the spots in my studio where I needed to kill reflections - exactly what you are trying to do Kyle.

I read the acoustics FAQ and then followed the panel construction instructions on the Music Player Group's EQ Magazine acoustics forum run by Ethan Winer - the SMC TOS don't permit us to post direct links to another forums as I understand them, so to find it, you'll have to do a web search on "Ethan Winer Acoustics Forum". Check out the READ THIS FIRST thread and go from there. Here are a few pictures of my panels that might help:

http://www.jardini.com/NewStudio/CIMG1032s.jpg

http://www.jardini.com/NewStudio/CIMG1041s.jpg

http://www.jardini.com/NewStudio/CIMG1052s.jpg

The frames are glued/braded together, then some mosquito netting is stapled on the back, then the 4" thick acoustic fiberglass panels are inserted and finally the front/sides are covered with whatever acoustically transparent cloth/material you can get cheap (using 3/8" staples to hold it all in place). Whatever material you use on the back and front must be acoustically transparent. The test for this is to hold a piece of it over your mouth and blow - if you can blow through it, it's okay, if not, look for a different material.

The panels should ideally be hung with a 4" gap between the back and the wall, but as little as 2" seems to work almost as well. Fixing these panels directly to a wall will not work! I have found these panels to be very effective.

HTH,

[Al Willits]

Dave's panels are basicly the same ones that I have the plans for, or with a bit of a search you can go to the Sound and Vision forum and find them.
Mr. Winer frequents that forum a lot and has added his abundate knowlege to the acoustic discussions there.

The plans on that forum will give you a bit better description on how to build them, Corning 703 fiberglas is considered best...I think its made by Corning anyway, but it is 703..
Hard to hang these from ceilings I'd think though, probably need some sort of grill to keep them from sagging.

Al

[Kyle Kraft]

Thanks, Dave and Al for the additional ideas and pictures! I will give it a go when time permits.

[Al Willits]

Here's a start on building your own panels, bit long though.

http://forums.soundandvisionmag.com/audiovideo/board/message?board.id=57&thread.id=7630

Al....who hopes off topic web sites are ok?

[Andrew Williams]

Now we are getting into a field that I have some pro experience in. I have been a recording engineer since around 91 or so, had to design and build a studio from scratch in NYC back then, and that was what brought me toward woodworking.

If you are looking to stop reverberation then I don't think basstraps are necessary. Most of the framed designs using 703 and fabric are basstraps designed to absorb lower frequencies than the usual convolution foam that people put on their walls. I am not saying these are bad. In fact, they may be slightly better at absorbing the overall volume from machinery. The painful frequencies, however are mainly higher than that. Fortunately, this is easier to deal with by far. You only need one layer of the stuff.

I constructed many different types of treatments and also bought sonex, auralex and some el cheapo convolution foam. I used 703 in flat panels along the wall, covered with burlap, and that worked great, but you will breathe in fiberglass over time, since it never seems to stop giving off dust unless there is a vapor barrier, which then hurts the sound absorbing characteristics. Personally, I would go with rockwool. It is far less flammable than foam, and has fewer health issues than 703. If you are not worried about fire, then just go to a foam dealer and have them run you off some wide sheets of acoustic convolution stuff. It is not up to recording studio par, but perfectly usuable to dampen machine noise.

My .02

Andrew

[glenn bradley]

You're on the right track. Soft materials will absorb the mid and high frequencies; clangs rattles and whining small motors. If you're getting a roar effect from low frequency resonance you can kill it with a bass trap if you've got room. They can be built into corners or up in open rafters with reasonable success:

http://www.ethanwiner.com/basstrap.html

[Andrew Williams]

A very effective basstrap if you have space for it is to buy a bunch of fiberglass insulation rolls, leave them all wrapped up and stack them up to make cylinders in your corners. Cover them with fabric and viola! the 15 minute basstrap.

[Dave Fifield]

A small point, but worth making I feel: the panels I made (as described in this thread, above) are WIDEBAND ABSORBER panels - they are NOT bass traps. Bass traps are only really useful if you have a specific low-frequency room resonance that you need to kill.

For wideband absorber panels like I made to work properly, you have to use the right fiberglass. I used John's-Manville 817 which is about equivalent to the Owens-Corning 703 stuff. I could only find it in 2" thick, so I doubled it up to make the required 4" thickness.

HTH,