Acoustic Room Treatments - Fabric Questions

[edham]

I have read the various threads on acoustic treatments and in particular the threads about 703, 705 etc.

My questions are about the effect of various fabrics used to cover a 705 type trap.
My room is small (ah...life in NYC) and this leads me to want some sort of pattern in the fabric since there will be very few other visual elements in the room.

The Guilford fabrics just aren't doing it for me asthetically. The colors are less then interesting and if I did the room in black ... well .... it would end up a BLACK room.

So - how do cotton, polyester blends or silk affect the absorbtion of the traps?

thanks in advance for any advice and/or pics that you guys post.


Kudos to Ethan, the real traps guy, the GIS guy etc etc. The willingness to share information and help out the DIYers is really cool.
I have been reading forums since .... well the earliest days of the DUC. I well remember the musicplayer forums at their pinnacle (96k thread anyone??? and where the hell is Nika these days?). I burnt out on audio forums after that and failed to make the transition to gearsluts. MY LOSS.
This forum is off the hook with knowledgable members who share info freely.
My compliments to all GS members and of course Jules.

[jayfrigo]

Originally Posted by edham

The Guilford fabrics just aren't doing it for me asthetically. The colors are less then interesting and if I did the room in black ... well .... it would end up a BLACK room.

So - how do cotton, polyester blends or silk affect the absorbtion of the traps?

thanks in advance for any advice and/or pics that you guys post.

Guilford has fabrics other than the 701, which is the classic choice for acoustic treatment.

Generally, the tighter the weave, the less effective the high frequency absorption. If you use upholstry fabric with a backing (like a gluey or rubbery sealon back), it won't be transparent to mids and highs, which means sound in that range doesn't get through to the absorber, but rather reflects much of the energy. Lows will still get through and bass absorption can still happen, depending on the construction of the trap. There are certainly some variables here. Also, to generalize, shiny fabric is more likely to be increasingly reflective at high frequencies. You usually want something fairly soft and with a coarse weave. Your wife's quilting fabrics aren't the best choice. The fabric does have an impact, but if you take that into account, and choose something not too far outside the norm, you should have a wide variety of styles to choose from and still be able to effectively control sound.

[jajjguy]

Get a sample of whatever you're considering and hold it up to your mouth and try to blow through it. If you can easily blow through it, then it's relatively transparent. This is an approximation, obviously, but it's a lot easier than running a real test.

[Glenn Kuras]

>So - how do cotton, polyester blends or silk affect the absorbtion of the traps?<

As jajjguy pointed out blowing through it is a good way to tell.. If absorbtion is your number one goal (which is should be) when building your own traps, then look deeper into the Guilford line.

Glenn

[drew]

i thought the fabric was supposed to be acoustically transparent? isn't that the way Guilford promotes it?

[matt thomas]

Originally Posted by jajjguy

Get a sample of whatever you're considering and hold it up to your mouth and try to blow through it. If you can easily blow through it, then it's relatively transparent. This is an approximation, obviously, but it's a lot easier than running a real test.

Yup, thats how you do it. I normally use hessian, which I think you americans call burlap (?)

narco

[Ethan Winer]

Drew,

> i thought the fabric was supposed to be acoustically transparent? isn't that the way Guilford promotes it? <

The only time you really need "acoustically transparent" is with speaker grill cloth in front of a tweeter. With an absorber panel, if the fabric absorbs a little more on its own, no harm is done. So what really matters is that the fabric doesn't reflect mids and highs.

--Ethan

[edham]

So what's a good rule of thumb on determining if a fabric is reflective to mids and highs?

Softer is better?

Hard and shiny is bad?

etc

Thanks gents!

[crna59]

I'm building a high-end Post and Mastering facility now. These guys are supplying all my materials, even the fabric. Give them a look!

Kinetics Noise Control

Regards,

[Ethan Winer]

Ed,

> Softer is better?
> Hard and shiny is bad?

Yes, exactly.

--Ethan

[edham]

thanks ethan! makes sense.

Anyone use silk??
I found a beautiful japanese print in a light weight silk. Seems like it would work well.
It breathes a bit and is super soft.

??????

[jayfrigo]

Originally Posted by edham

So what's a good rule of thumb on determining if a fabric is reflective to mids and highs?

Softer is better?

Hard and shiny is bad?

Look a few posts above... tight, hard, shiny, sealed in back.

[stevep]

Originally Posted by jajjguy

Get a sample of whatever you're considering and hold it up to your mouth and try to blow through it. If you can easily blow through it, then it's relatively transparent. This is an approximation, obviously, but it's a lot easier than running a real test.

[Shandy]

Burlap's the stuff. Has a nice, loose weave, and a fairly irregular surface. Provides very little reflection and allows a fairly wide frequency range to pass through. PLUS, it's perfect for the "fiscally challenged" (read as 'cheap,' 'broke,' etc.,..) as it can be had at Wal-Mart and similar stores for a buck-something per yard.

Comes in a variety of colors, too, for those with a color scheme to maintain.

I had a friend who covered his DIY broadband absorbers with old coffee bean sacks-- they had all kinds of printed logos and warnings on them. Looked very cool...

[Joel DuBay]

Ah, Fabric.....


edham,

I concur with my acoustic counter parts about acoustic fabric for the most part.


My 2 cents:

Make Fire Resistance (fire ******ant) a number one priority. As a NY tenant, chances are, this is required by your lease in some way, shape or form. And, it makes good, practical sense. Many acoustically "breathable" fabrics are fire resistant/ fire ******ant. NONE are fire proof as everything has a flash point.

With regard to "breathability". More than anything, the "breathe" test should eliminate fabrics, rather than be an acceptance factor for such. If you cannot breathe through the fabric you are interested in, or you must ad extra force to penetrate the fabric with air, then you'll want to steer clear of it for absorptive purposes. However, if the fabric does offer some breathability, it may very well work for you. Some "shiny" fabrics are said to have reflective properties, though I cannot 100% agree that this is the case for all frequencies outside of the bass range. There are numberous articles that point to "shininess" as a determining factor for not using a particular fabric for absorptive purposes, but I am not aware of anything conclusive that excludes it all together. I am CERTAIN "someone" will make an effort to correct me if I am incorrect.

Some fabrics offer a slight stretch to them, and as such may make good acoustical fabrics as well. When a fabric is stretched, the weave opens to some degree and makes the fabric more transparent than it is at rest.....something to consider perhaps.

In the end, the fabric you are looking at and like may make a decent covering for your acoustical treatment. However, it must be breathable if you want your treatments to be absorptive. If you are looking for bass absorption only, just about anything (even shiny fabrics) will do.

Make sure you are happy, and safe no matter your choice.


Good luck,

Joel

[Jason Poulin]

We're using speaker grill cloth.


It's real transparent. Very light.




Good luck!


Jason

[Bounce]

Does anyone know if there's a good spray fire ******ant that would work on my acoustic treatments? I used 100% cotton breathable fabric on my new panels and burlap on my old ones and was wondering if there is a treatment that won't compromise the flow of the fabric...Anyone? Thanks :-)

[Joel DuBay]

Originally Posted by Bounce

Does anyone know if there's a good spray fire ******ant that would work on my acoustic treatments? I used 100% cotton breathable fabric on my new panels and burlap on my old ones and was wondering if there is a treatment that won't compromise the flow of the fabric...Anyone? Thanks :-)

There many fire ******ant sprays available on the market. You can find at least 3 of the top brands at home stores and The Home Depot.

Keep 2 things in mind. Because your fabric fibers are not impregnated with a fire ******ant chemical, you will have to re-apply the spray at intervals specified by the manufacturer.

When you do use a spray of this sort, you must do so in a very, very well ventilated area, preferably out of doors.


Good luck,

Joel

[Bounce]

Hey, Joel, thanks for the info, buddy! I was most concerned with them drying hard and compromising the integrity of the airflow through the fabric...

[Joel DuBay]

Originally Posted by Bounce

Hey, Joel, thanks for the info, buddy! I was most concerned with them drying hard and compromising the integrity of the airflow through the fabric...

That certainly is something to consider. The fabric we make is impregnated with a fire ******ant chemical, so I cannot speak to how a spray-on may adversely affect sound wave penetration.

My guess is that is will probably not impede this much, but I just cannot say for certain.


~ Joel

[cajonezzz]

I just went through this drill.... Went to UFO fabrics here in Oceanside Ca, and looked at EVERYTHING. I ended up with Black grill cloth, 9 bucks a yard, 5.5 ft width.
It's spread over open stud walls with R-13. I'm going to be hanging 18 of the ready traps as well.

There were some fantastic fabrics there as well, gorgeous colors and all- but a little rich for my blood. I'll probably dress up the black walls with some groovy pics and tapestry type stuff.


cz

[dredbird]

Originally Posted by jayfrigo

Look a few posts above... tight, hard, shiny, sealed in back.

I just picked up some canvassy-type monk's cloth. It's hard and I would guess tightly woven.

I figured it would be okay, but ... bad idea?