ideas for speaker baffle treatment? cork?

[bbaker6212]

What is a good material to use on the front of a speaker baffle to reduce reflections? I was thinking cork would be a cheap thing, but other's may look better.

ideas?

[roddyama]

Hi Brad,

I've always used 1/4", medium weight, closed cell foam rubber. It's easy to work with, easy to attach, and readily available (in urban areas). It does a good job above about 1kHz.

Heavy felt (1/4") would be better, but it's a bit tougher to work with and very difficult to find. You could dye it to meet you esthetic requirements and I would expect it to damp well down to possibly 500Hz or so.

Rodd Yamashita

[navin]

i have use open cell foam but since we get it only in white here i cover it with a black cotton cloth. the cotton cloth is not very thick very thin in fact aslmost tranlucent but it covers the foam well.

i have alos used felt but sincethe colour i got cheap was red i had it dyed. once could always srpay paint it.

[SY]

Felt is the classic. For an all-out design, layers of different thickness and density can provide hours of experimental fun.

If you're going to use foam rubber or plastic, open cell is much more effective. Again, a multilayer system can be quite effective; one set of speakers I built used three densities, with 8 pcf at the bottom, going to 6 pcf, and 4 pcf at the surface.

[dana]

I have used cork several occasions when I simply didn’t want to make router templates for recessing odd shaped driver frames. Cork sheet is readily available, comes in a variety of gauges and is very easy to cut.

If you are careful, the driver can be used as a template for cutting the cork. If the cut is tight enough to the frame edge (cork in sheet form is somewhat elastic), the cork will make a very snug and flush fit with the driver.

Unfortunately, thicker cork sheet does not bend easily. If you want to follow a baffle edge radius, make sure the radius is sufficiently large. I have not tried to trim it with a router, but I suspect that unless the bit was new routing it may tear it up.

I got the idea to use cork as a baffle veneer from looking at one of Be Yamamura’s loudspeakers at CES a number of years ago. Yamamura claims that cork sounds better than other materials, because it is natural and inherently well damped. While I have no specific insight into that claim, I did find the the finished speaker I built did sound very good, but really can’t say how much, if any, cork contributed to the overall sound.

Cork does look a little like particle board, but has a much nicer color. I have found that if it is applied and detailed correctly, it can look rather elegant.

[fdegrove]

Hello,

If you really want to cancel all frontpanel baffling:

Design for dedicated housing of you units a la B&W Nautilus.

If that's not feasable stick a sorbothane sheet on the frontpanel making sure you only leave the membrane/piston unimpeded.

This elastomer was used by the military to camouflage aircraft and submarine from radar/sonar signals.

Doing so will give a a near perfect point source.
It can also be put to good effect on the inside of the speakercabinet where it will effectively cancel resonance especially when used asymmetrically.(which I always do regardless of damping material)

My

[planet10]

Originally posted by roddyama
Heavy felt (1/4") would be better, but it's a bit tougher to work with and very difficult to find.

Felt works well. The sample in the picture was salvaged from a set of 20 year old Marsland speakers.



I figure that if i stiffen the backside with glue i can use it for a grill frame.

I also have all the raw material to make my own felt and was going to experiment with moulding it.

dave

[SY]

Rodd, heavy felt is easy to find. Good ol' McMaster-Carr comes through again.

BTW, Frank, I seriously doubt that Sorbothane has any use against radar signals. You might check out The RCSR Handbook for materials that do.

[roddyama]

Sy,

I don't know why, but I never thought to look in the Mac-Car catalog for felt, I should have known.

There's a foam rubber store 2 miles from me. They carry anything from neoprene to bass foam rubber you can almost see through.

Rodd Yamashita

[SY]

Over the past several jobs I've had, I learned that if McMaster-Carr doesn't have it, you don't need it! The catalog is a terrific design engineering reference, too. I' m continually amazed that they can get stuff to me so fast.