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Title: Sound absorption on the cheap
Post by: Brad Ferguson on December 06, 2008, 08:41:34 pm
So, my friend, the club owner, has asked me to source out material to deaden down his stage at his club.

It's a very low drywall ceiling, and has glass windows on the upstage wall.

He doesn't care if he covers the windows.

I suggested to make some 2' wide by whatever deep panels, and connect them to the ceiling, and to mount on the upstage wall.

He said "GREAT! Can you source out everything for me?"

Of course I said yes.

So, now I'm looking for suggestions as to what type of foam, or material I should think about using for this - he doesn't want to spend too much money, of course.

Any ideas/suggestions would be appreciated!
Title: Re: Sound absorption on the cheap
Post by: Adam Whetham on December 06, 2008, 08:45:36 pm
The only two options I recommend to people anymore is:

A: Flame Retardant treated Drape.

B: A professional solution from Auralux or Acoustical Solutions or someone like that.

Anything else just rings Station fire.
Title: Re: Sound absorption on the cheap
Post by: Dick Rees on December 06, 2008, 08:46:14 pm
http://www.auralex.com/

On the cheap may be flammable and/or uninsurable.  Don't touch anything like this unless you can afford to hand everything you own over to the lawyers.  Get a licensed, bonded contractor.
Title: Re: Sound absorption on the cheap
Post by: Ivan Beaver on December 06, 2008, 08:52:12 pm
The cheapest stuff I would recommend is a DIY project using Duct Board (compressed fiberglass used in the HVAC industry) and covering with a FLAME RETARDANT fabric.

Be forewarned the fabric will probably cost more than the fiberglass material Shocked .

Try to use 2" thick.  This is not as good as 6lb "acoustical" fiberglass, but is available locally and will be less expensive.

WHATEVER YOU DO, use ONLY products that will not burn!!!!!! Or you could be held liable in the event of a fire.
Title: Re: Sound absorption on the cheap
Post by: Rick Powell on December 06, 2008, 09:08:03 pm
Forget Auralex or other foam based products.  They are highly flammable without treatment and deaden high frequencies without attenuating bass, creating dull and yukky sound.  Foam can be used effectively, but not without a lot of good planning and extra expense to counteract what the foam does to the sound.  The best day in my recording studio was when I ripped all the Auralex down.

If you are looking CHEAP and effective, order raw Knauf or Owens Corning 2' x 4' fiberglass panels from ATS Acoustics in Piper City, IL, and cover them in their flame-retardent burlap.  The greater the thickness, the greater the bass absorption.  They come in 1", 2" and 4" thicknesses, and also offer rock wool which is a little tougher to work with.  ATS will make the panels for you, but you can DIY cheaper.

http://www.atsacoustics.com/cat--DIY-Acoustic-Materials--102 .html
Title: Re: Sound absorption on the cheap
Post by: Dick Rees on December 06, 2008, 09:14:21 pm
Rick Powell wrote on Sat, 06 December 2008 20:08

Forget Auralex or other foam based products.  They are highly flammable without treatment .....


http://www.auralex.com/auralex_acoustics_faqs/fire_retardanc y_faqs.asp

I think you should check this out a little further.

Your experience seems to be limited to only one of their products.  They do indeed make bass reduction systems.  Look at their whole line.  It will give you some good ideas if nothing else.
Title: Re: Sound absorption on the cheap
Post by: Randy Pence on December 06, 2008, 10:13:46 pm
Wrap rockwool or owens corning 703 with fire resistant treated fabric, as Ivan suggested.
Title: Re: Sound absorption on the cheap
Post by: (Brian) Frost on December 07, 2008, 01:50:49 am
rockwool or 703 will work well, but you will have to build a lot of them.  If you have a lot of area to cover, heavy duvatine is also an option.  Its generally found in large pieces, should always be fire retardant, and has both a shinier and a matte side.  Makes for nice reasonably priced curtains.  Only helps with the high end but can help a large live area quite a bit.  
Title: Re: Sound absorption on the cheap
Post by: Josh Billings on December 07, 2008, 07:17:47 am
Great suggestions on here, i don't think i need to add too much more.

Be sure to locate some behind the speakers as well and band to minimize the reflections.

-Josh Billings
Title: Re: Sound absorption on the cheap
Post by: Brad Weber on December 07, 2008, 08:24:48 am
Dick Rees wrote on Sat, 06 December 2008 21:14

Rick Powell wrote on Sat, 06 December 2008 20:08

Forget Auralex or other foam based products.  They are highly flammable without treatment .....


 http://www.auralex.com/auralex_acoustics_faqs/fire_retardanc y_faqs.asp

I think you should check this out a little further.

Your experience seems to be limited to only one of their products.  They do indeed make bass reduction systems.  Look at their whole line.  It will give you some good ideas if nothing else.

I think the point is simply that some of the available acoustical products are not appropriate for public venues and you need to be careful to select the proper products, some products intended for studio or home theater use may not be appropriate in public venues.

I'd also add Kinetics Noise Control (http://www.kineticsnoise.com/interiors/) or Tectum (http://www.tectum.com/) as options for panels, baffles, etc. and K-13 (http://www.internationalcellulose.com/home/products/k-13/) as an option for the ceiling.  The spray-on ceiling treatments are often fairly cost effective compared to baffles.

Not knowing the club, you may need to consider factors such as durability, ease of replacement, washability and even appropriateness for food prep or eating areas in looking at finishes and materials.
Title: Re: Sound absorption on the cheap
Post by: Randy Pence on December 07, 2008, 09:22:00 pm
Yes, treating the stage will make mixing easier.  I had originally read doing the floor, but I would do both if possible.

With rockwool, one does have to build a lot of panels, but they are very effective.  Spacing them from the wall will increase lf performance.  I like modular ideas in a club, because you never know what someone will do to a big piece of material.  Washing fire retardant fabric can remove the protective coating!
Title: Re: Sound absorption on the cheap
Post by: Jason Dermer on December 07, 2008, 10:24:32 pm
Find a bonded/ insured acoustic design company.

Pay them to do the work safely and properly.

Enjoy your SAFE, better sounding room.

Unless you are willing to take the chance at making the sound worse and have the insurance to cover the possibility of EVERYONE at your gig DYING, There are no other options.


As I have mentioned multiple times in the past, the last Great White show before the Station disaster was at one of my house gigs, so I do not take the sound deadening issue lightly. Do it right, or stay away.
Title: Re: Sound absorption on the cheap
Post by: Micah McFadden on December 08, 2008, 01:01:53 am
You need to find some acoustically transparent fabric to get the most out of the absorbers you will be putting up.   I suggest

using some Guildford of Maine FR701 fabric.  This fabric is a bit expensive, but it seems to be the #1 choice for acoustic

professionals when building broadband absorbers.  If you want some fabric that will perform the same for less money, I would

suggest this fabric:        http://www.acoustimac.com/index.php?page=shop.product_detail        s&flypage=shop.flypage&product_id=22&category_id        =5&manufacturer_id=0&option=com_virtuemart&Itemi d=21

I did not see whether or not this fabric is fire treated or not.  I know the Guildford of Maine fabric is treated and they

even provide data sheets for you to show to the fire marshal who might happen to ask about that fabric you have hanging on the

wall.   For other acoustic materials you might want to check here:         http://www.acoustimac.com/index.php?page=shop.browse&cat egory_id=11&option=com_virtuemart&Itemid=21

Title: Re: Sound absorption on the cheap
Post by: Micah McFadden on December 08, 2008, 01:18:21 am
Also another tip would be to try and use at least 2 inch thick panels.  The thicker the panel the lower in frequency it will

absorb.  A thin panel will only reduce the upper frequency range, while still allowing the mids to reflect off the wall.  Using at

least 2 inches thick will help get the absorption down into the mids.  I would also suggest using Owens Corning 703.  You should

be able to find a local insulation place that would have it in stock, or you can easily buy it off of many websites and have it

shipped to you.
Title: Re: Sound absorption on the cheap
Post by: Tim Padrick on December 08, 2008, 02:33:56 am
Corning also makes SelectSound, which is basically 703 in black, so the cloth has a better chance of hiding the color.
Title: Re: Sound absorption on the cheap
Post by: Dick Rees on December 08, 2008, 09:49:35 am
Jason Dermer wrote on Sun, 07 December 2008 21:24

Find a bonded/ insured acoustic design company.

Pay them to do the work safely and properly.

Enjoy your SAFE, better sounding room.

Unless you are willing to take the chance at making the sound worse and have the insurance to cover the possibility of EVERYONE at your gig DYING, There are no other options.


As I have mentioned multiple times in the past, the last Great White show before the Station disaster was at one of my house gigs, so I do not take the sound deadening issue lightly. Do it right, or stay away.


+1.  The longer I'm at it, the less I care to alter any building construction.  You CAN be held liable even if someone else screws up what you did right.  When the S*** hits.......they'll sue everyone who walked in the front door with a hammer.  Don't let that be you.

On a side line:  Low frequency control does not rely entirely on absorptive material.  A certain amount of dead space contained by the proper materials (bass trap) will really do the job.  The problem is that you have to have the space to waste.
Title: Re: Sound absorption on the cheap
Post by: Art Welter on December 09, 2008, 02:12:27 pm
Brad,

All the prior posts about having it done right, and making sure anything installed is fireproof is good advice.

However, all the ideas so far mostly only deaden the high frequency, which often make lower frequency problems even more apparent by comparison.

Another approach not mentioned so far that works quite well in small and larger scale rooms is a type of diffuser panel I encountered in an orchestral rehearsal room.

The room was a typical ballroom type room, about 70’ x70’ and 10’ ceilings. I expected it to sound like the usual boom boom room, but was surprised to find I could run my system at upwards of 115 dB (where it was running out of headroom) without any of the flutter echoes, boom or the other crud associated with that type of room shape.

I later built the same type of panels for a friend who wanted to turn his cinderblock single car garage (probably roughly the size of the stage you are trying to fix) into a rehearsal/recording studio.

Each panel uses a piece of 4’x8’ 1/4” ply bent on arcs which are cut from 2”x12” material. Picture the cross section of a parabolic satellite dish vertically attached to a frame, like an airplane wing, or a giant roll and pleat.

The back side of the frame has fiberglass insulation installed. The sections I made, and the ones I copied, used 4’x8’ 1/4” ply. If your ceiling is higher, the “wing” could be made higher.

The arcs were cut to a 4” depth if I recall correctly, with a 1.5” frame thickness, for a total depth of just under 6” in the center. The arc is a section of a circle with approximately 57.5” radius. Four arcs per 4’x8”, and 1.5” angled “studs” on either side. The left to right dimension is slightly under 48” because of the arc, so you need to lay one up to figure exactly how many sheets you need for the finished length.


The reverse parabola scatters, rather than absorbs the sound waves, the spectral content stays roughly the same, while the standing waves and HF chatter are largely eliminated. The 1/4” material flexes enough that it (with the fiberglass behind) eliminates much of the mid-bass build up common to a small room.

I can not normally stand to be on a small live stage without hearing protection with even a moderately loud drummer. With this type of treatment not only do drums sound good, but everything is easy to hear distinctly throughout the room. Stage volume escalation should  tend to be less than on a “dead” stage, where musicians crank up because their apparent volume seems less, or a too live stage where they crank up to hear themselves over the wash.

Cutting the arcs with a band saw took a while, but the rest of the construction is about the equivalent of doing a sheet rock wall of the same size.

Art Welter

P.S. Really large sonotubes could be cut up for a similar effect as what I described above, and would be a snap to install.

Title: Re: Sound absorption on the cheap
Post by: SteveKirby on December 09, 2008, 02:37:42 pm
One small suggestion, while it may seem like a good idea, try not to totally deaden the area behind the drummer.  Drapes or other HF absorbtion kills the sound of the kit and tends to make the drummers bang harder.  A bit of diffuse reflection behind them will let them balance themselves better with the rest of the band.

First order of treatment should be along the sides and rear corners of the stage and then the short dimensions of the room.
Title: Re: Sound absorption on the cheap
Post by: Brad Weber on December 09, 2008, 04:16:57 pm
Art Welter wrote on Tue, 09 December 2008 14:12

The reverse parabola scatters, rather than absorbs the sound waves, the spectral content stays roughly the same, while the standing waves and HF chatter are largely eliminated.

I agree that convex diffusers can be very effective and any diffusion would probably help however convex or 'barrel' diffusers are one dimensional diffusers and are spectral, the overall size and depth of the diffusers will affect the frequency range over which they are effective.  Providing elements of varying size and radii can help provide effectiveness over a wider range and having varying orientations can also help with ceiling applications.

Other similar options might include pyramidal diffusers, which are two dimensional diffusers and for which some of manufactured units are asymmetrical and can then be randomly rotated to provide more random diffusion.  Another option, although not necessarily for those on a tight budget, might be RPG BAD or Kinetics TAD panels which are absorbers at lower frequencies and transition to binary diffusers at higher frequencies, similar to what was apparently intended with the custom built panels noted but with two dimensional diffusion.  If budget is even more forgiving, then RPG Omniffusor, Abffusor or QRD panels might even be an option.
Title: Re: Sound absorption on the cheap
Post by: John Halliburton on December 09, 2008, 05:11:27 pm
Brad Weber wrote on Tue, 09 December 2008 15:16

Art Welter wrote on Tue, 09 December 2008 14:12

The reverse parabola scatters, rather than absorbs the sound waves, the spectral content stays roughly the same, while the standing waves and HF chatter are largely eliminated.

I agree that convex diffusers can be very effective and any diffusion would probably help however convex or 'barrel' diffusers are one dimensional diffusers and are spectral, the overall size and depth of the diffusers will affect the frequency range over which they are effective.  Providing elements of varying size and radii can help provide effectiveness over a wider range and having varying orientations can also help with ceiling applications.

Other similar options might include pyramidal diffusers, which are two dimensional diffusers and for which some of manufactured units are asymmetrical and can then be randomly rotated to provide more random diffusion.  Another option, although not necessarily for those on a tight budget, might be RPG BAD or Kinetics TAD panels which are absorbers at lower frequencies and transition to binary diffusers at higher frequencies, similar to what was apparently intended with the custom built panels noted but with two dimensional diffusion.  If budget is even more forgiving, then RPG Omniffusor, Abffusor or QRD panels might even be an option.



Varying the curvature of the curved diffusers shouldn't be much of a problem.  Also, a more accurate method of cutting arcs out of 2x12's(I'd use sections of Baltic Birch plywood, but that's me) would be to make a pattern for a router to follow using a bearing bit or template bushing installed in the router base-common accessories for the router.  1/4" plywood should still flex fairly easy to even a 24" radius, probably smaller, depending on the plywood type.
As Art also mentioned, this could be done using Sonotube, and you could just buy a selection of diameters to slice up lengthwise, make a frame to hold a set of these slices, and fill the backside with insulation. Sonotube is available 22 diameters from 6"-60", and lengths from 3-20'.  Fun!

Best regards,

John
Title: Re: Sound absorption on the cheap
Post by: Randy Pence on December 09, 2008, 05:37:29 pm
Does this mean you won't plug in a power cable because someone could slice off the end and electrocute themselves?

Fire, like tools of power, and electricity, is something to respect, not fear.  Testing flammability is also very easy.  A flame (such as from a lighter) on treated material will immediately extinguish once the flame is removed.  The fire marshall can pick out any spot they want and light up.
Title: Re: Sound absorption on the cheap
Post by: Art Welter on December 09, 2008, 10:25:42 pm
John,

I normally use a router for repeatability, but in the case of making these arcs, using a band saw was faster and saved quite a bit of material.

The OP wanted cheap, so Baltic Birch was out, and in this application, flexible is actually better so cheap and cheerful is good.

If I would have known about the large diameter Sonotubes at the time I did this work, would have used it, it would have been cheaper and easier than the plywood “wings”.

Art
Title: Re: Sound absorption on the cheap
Post by: Chad Johnson on December 10, 2008, 12:25:07 am
Here's a pic of a room I did with large polycylindrical diffusors and tectum panels in between. The diffusors are good for mid and high band diffusion and low band absorption. Tectum is used with large air space in corners for more bass absorption. The tectum wall panels can be painted and are fire rated. They are fired out from the wall 2" and Roxul is used in the air space behind, they are very effective broad band absorbers.

index.php/fa/19548/0/

Edit: There's also suspended ceiling tile over the stage area and interspersed throughout the performance area.  RT 60 was taken from 8.9 down to around 2.6.
Title: Re: Sound absorption on the cheap
Post by: Brad Ferguson on December 10, 2008, 02:22:34 am
Thanks for all the suggestions, guys!  I knew I could count on the big brains on this board to help me out.

I'm not too worried about absorbing LF information - the big problem is basically snare drums ringing way too loudly off the stage.

I'm sourcing some 703, and I'm going to basically cover some ply with it, and some material.  Should be cheap enough, and I have some lines on some fire resistant material.

Title: Re: Sound absorption on the cheap
Post by: drewgandy on December 10, 2008, 08:29:43 am
Brad Ferguson wrote on Wed, 10 December 2008 01:22

Thanks for all the suggestions, guys!  I knew I could count on the big brains on this board to help me out.

I'm not too worried about absorbing LF information - the big problem is basically snare drums ringing way too loudly off the stage.

I'm sourcing some 703, and I'm going to basically cover some ply with it, and some material.  Should be cheap enough, and I have some lines on some fire resistant material.




I don't think its been mentioned yet that many fabrics can be treated for flame resistance.  http://www.rosebrand.com/category16/flame-retardant.aspx
You would have to weigh out the costs of buying pre-treated (and inherently flame resistant) or buying something cheaper and treating yourself. And of course, a call to the fire marshall about regulations and how they want you to document this stuff would be a good idea.  

Also, years ago I found that mineral fiber was cheaper and offered similar performance (actually slightly better performance) to 703.  I understand the idea to use plywood as a backer but you may also consider cutting out the "center" of the ply in order to take some advantage of the spacing from a boundary.  The idea is that you leave the perimeter as a surface  to staple the fabric to and to use for effective mounting but sound can still pass through most of the panel to the boundary behind.  2 inch material spaced 2 inches from a wall offers almost as much absorption as 4 inch material fastened directly to a wall.  For most of my applications, I've found that 1.5 inch material spaced 1.5 - 2 inches from a wall is the best performance/vs dollar option unless you are really trying to absorb bass.  There is a lot to consider acoustically and in some cases overthinking it may not be worth it. Just getting some material up and seeing how it affects things....

drew
Title: Re: Sound absorption on the cheap
Post by: John Halliburton on December 10, 2008, 10:09:16 am
Art Welter wrote on Tue, 09 December 2008 21:25

John,

I normally use a router for repeatability, but in the case of making these arcs, using a band saw was faster and saved quite a bit of material.

The OP wanted cheap, so Baltic Birch was out, and in this application, flexible is actually better so cheap and cheerful is good.

If I would have known about the large diameter Sonotubes at the time I did this work, would have used it, it would have been cheaper and easier than the plywood “wings”.

Art


Agreed, I think I was trying to convey that technique can vary according to comfort level/familiarity with certain tools, along with what you have available.  Since I tend to have more Baltic Birch plywood scrap around v. lumber, and use a router a lot, that's just how I'd consider doing the job.  I'm certainly not against the jigsaw, I've owned one of the great Bosch(EV?) units for many years.
I've been tossing around building some of these diffusers for many years, to take down to the venue I do a lot of work at. This has been another informative thread on the subject, especially for sourcing out absorption materials.

Best regards,

John
Title: Re: Sound absorption on the cheap
Post by: Brad Weber on December 10, 2008, 10:18:24 am
The problem with most homemade solutions is that the performance is unknown, you cannot perform any accurate prediction or analysis with them.  As a result, recommendations for homemade treatments are typically based on providing an undefined change rather than a specific change or result.  This does not diminish the potential value of them but it does mean that one often can't predict the results or plan on obtaining any specific improvement or result where that may be desired.  Probably not an issue in this particular application but more often a factor in some other applications.

Since some of you seem to have more familiarity with using Sonotube, are you aware of any actual performance testing or published data?  Has anyone confirmed that they are approved for use in public spaces?  Does anyone else wonder why Sonotube does not seem to mention or promote this use?
Title: Re: Sound absorption on the cheap
Post by: Tim McCulloch on December 10, 2008, 11:59:16 am
It's been a long time since I've used Sonotube for anything... but 20 years ago it was wax-impregnated cardboard.  I suspect it would not meet smoke density or fuel contribution criteria for use in wall coverings.  I'm not sure if untreated plywood would, either.

That said, as long as they weren't attached to the walls (permanent installation) or used to delineate work spaces (like office cubicles), they *might* not get a second look from the fire marshal.  I could be wrong...

A big part of the reason architectural finishes cost big $$ is to pay for the testing & certification of prototypes and continued QC for produced goods.

Tim "safety is GOOD" Mc
Title: Re: Sound absorption on the cheap
Post by: Jamin Lynch on December 10, 2008, 01:08:55 pm
Check out Perdue Acoustics. You may think their panels are expensive, but they are so efficient you need far less than most other panels which makes the over all cost less. Plus they have a wide variety of sizes, colors, and models to choose from.

I just finished a job using their panels and they far acceded what I was expecting.
Title: Re: Sound absorption on the cheap
Post by: Rick Powell on December 10, 2008, 09:37:04 pm
ATS's site as I linked to above, shows the test results of their 703/fabric solution.  A homemade version of the same could be expected to have similar results - it's not rocket science to build these things, and the material has consistent and well known properties.
Title: Re: Sound absorption on the cheap
Post by: Rick Powell on December 10, 2008, 09:45:37 pm
Brad Ferguson wrote on Wed, 10 December 2008 01:22



I'm sourcing some 703, and I'm going to basically cover some ply with it, and some material.  Should be cheap enough, and I have some lines on some fire resistant material.




If the 703 has an open backing (such as a frame, with the 703 covered with fabric on both flat surfaces), and the panel is spaced a few inches away from the wall, you will have twice the absorption area.  When you mount flush to the wall, or put a solid backing on the panels, you are giving away half the panel's effectiveness potential.  Just a thought.  ATS puts their panels in a wooden slat frame much like a bedding frame, so that both flat surfaces are absorptive.

RP
Title: Re: Sound absorption on the cheap
Post by: Brad Weber on December 10, 2008, 11:47:57 pm
Rick Powell wrote on Wed, 10 December 2008 21:45

If the 703 has an open backing (such as a frame, with the 703 covered with fabric on both flat surfaces), and the panel is spaced a few inches away from the wall, you will have twice the absorption area.  When you mount flush to the wall, or put a solid backing on the panels, you are giving away half the panel's effectiveness potential.  Just a thought.  ATS puts their panels in a wooden slat frame much like a bedding frame, so that both flat surfaces are absorptive.

If you spaced the panel several feet off the wall you could would likely get some effect from both sides but not at a spacing of a few inches.  That kind of spacing should help improve the low frequency absorption the panel provides but it has nothing to do with increasing, much less doubling, the effective surface area and I cannot find where ATS makes any such claim.  And unless you are referencing some other ATS Acoustics, they clearly state on their web site (http://www.atsacoustics.com/) that their standard acoustical panels, which are apparently offered only in 2" and 4" thicknesses, have a solid 1/4" wood back panel.  You can order the 4" thick panels without the wood back but it is not an option on the 2" thick panels.  Are you maybe thinking of some other manufacturer?
Title: Re: Sound absorption on the cheap
Post by: Brad Weber on December 10, 2008, 11:58:19 pm
Rick Powell wrote on Wed, 10 December 2008 21:37

A homemade version of the same could be expected to have similar results - it's not rocket science to build these things, and the material has consistent and well known properties.

It is the details like how you attach the fabric to and how you treat the edges that is where many DIY acoustical panel projects fail.  Most commercial acoustical panels have either a resin hardened edge for the actual substrate or use a plastic or metal edge, that is how they can get clean and consistent edges.  Many manufacturers also offer various versions of their panels such as abuse resistant 'high impact' panels with a material covering the substrate behind the fabric.  In some cases these other panel versions offer different absorption characteristics, there is at least one manufacturer offer a 'low frequency tuned' panel that use an internal septum for diaphragmatic absorption at lower frequencies.
Title: Re: Sound absorption on the cheap
Post by: Terry Duoos on December 16, 2008, 07:40:35 am
I love when they (owners) talk teck.

I'v seen so muchmoney and labor wasted ..spent for not on acoustics trying to better or eliminate...what is it?!@@#.

First where is the meat of the complain.
His bartender cant hear the orders over the band?

or is Mr Bitchalot next door  just not likened to heavy metal at 1am?

Gotta know where to spend and in which direction.

If its leakage that generates complaints then put a spectrum analyzer muic on that guys porch and ask him to tell when things
are not acceptable...i had a case where it was just the floor tom and no other sound....not the bass niot the gigawattarshall stack just thart one freq of that one tiom that resonasted so extremely much....Tried a couple of methods to filter down that freq..100-ish i think ...found it was a mode swet up wall rto wall where drums were sert up...built traps there where the pressure was max and done deal.

Lots of his money could in deed go to acoustic endevours..nice if it eliminated cause...not bandaid symptom...
Title: Re: Sound absorption on the cheap
Post by: Terry Duoos on December 16, 2008, 07:45:13 am
I ment to spell check ...sorry...
Typing with other hand.

terry