[NagysAudio]

Hi Everyone,

     Over the years building various speakers, I have came to the conclusion that the very best damping material is... Bubble Wrap!! Now this pretty much only concerns ported speakers. I have used everything from Dynamat, wool, fiberglass, Black Hole 5, fiberfill, etc.

In my experience, having an extremely dense, solid, non resonating box is much more critical than selecting damping material.

Having said that, bubble wrap gives a very fast mid bass and an extremely un-boxy midrange. Really nothing else gives me this result to my satisfaction, therefore nothing else comes close to bubble wrap. The type of bubble wrap that I use has small bubbles not large. It can be rolled up to a certain thickness and attached behind midrange, woofer, etc.

To describe this type of sound is difficult. When one is listening to the speakers, it seems like the sound originates right in front of the speaker drivers. One never gets the sense that the sound propagates through the box. It is extremely pleasing to the ear. It's as if the music lingers right in front of you.

Maybe the best way to describe it is this way... Lets say that it's a small bookshelf speaker using a 5" driver. You are listening at a fairly loud level to music which gradually builds up to drums. At that point, most small speakers start to sound very heavy handed, one is under the impression that they are close to bottoming out, or just not sounding normal anymore. With bubble wrap, even small speakers take the crescendo in a very light and effortless fashion. I love this quick, light and effortless presentation.

Sometimes when building ported speakers, only bubble wrap will be sufficient to get the desired effect. However, there are occasions where a 0.5-1.0" standard gray foam can help in addition.

As far as closed speaker boxes are concerned, fiberfill is always the champ.

Till next time,
Norbert

[Bill Baker]

I heard of this some time ago and even tried it out a few years back. Like any material used for this application, it will have an effect on the sound. My problem with this is safety. Bubble wrap is very flamable and should you have a voice coil overheat and near this plastic....... well, you get the idea.
 Most damping material used within a speaker has to meet strict requirements (at least for commercial use) and I always kept copies of the material's MSDS (Material Safety Data Sheet) on hand.
 There are still many people that use roofing paper, otherwise known as tar paper, within their speakers. Some using a tar/sand mixture. I even have one pair of speakers that I custom built myself for myself many years ago using a constrained layer of 1/8" thick lead sheet sandwiched between two pieces of 3/4" MDF. I used heavy pressure and silicon to sandwich the materials as well as assemble the panels afterwards (which required applying lacquer to the MDF for the silicon to adhere to). Talk about a heavy speaker. Obviously lead has it's own issues.
 My point was that every material used effected the sound in a different way and the bubble wrap idea has been around for a while now. By the way, I did like the results of the bubble wrap but didn't feel comfortable leaving it in.

[Vapor Audio]

I like a constained damping layer out of C4, and use det cord to damp the woofer baskets.  I figure if I'm getting into the music enough to cause a voice coil fire, what better time to go out?

[NagysAudio]

  TurnoFC3S, C4 will not explode that way, even if it's thrown into fire 

Bill, you are very correct that bubble wrap could catch on fire. When I used to work retail at an audio store, I've replaced many crossovers which looked like they came out of a barbeque pit.

However, I don't know about the strict requirements. I know of at least one major speaker manufacturer that use bubble wrap inside their speakers. Besides, I've looked inside hundreds of speakers and manufacturers use all kind of garbage which could catch fire.

[TONEPUB]

Well, I'm shocked!

[KCI-JohnP]

TurnoFC3S, C4 will not explode that way, even if it's thrown into fire

No but the detcord will which will inturn detonate the C4.

[Bill Baker]

Bill, you are very correct that bubble wrap could catch on fire. When I used to work retail at an audio store, I've replaced many crossovers which looked like they came out of a barbeque pit

.

I have actually been at parties, in my younger years, where I have seen smoke come from speakers that were driven far too hard only to pull out the crossovers and see the same barbecue grilled look.

However, I don't know about the strict requirements. I know of at least one major speaker manufacturer that use bubble wrap inside their speakers. Besides, I've looked inside hundreds of speakers and manufacturers use all kind of garbage which could catch fire.

 I agree, I have seen some pretty shabby materials inside of speakers but I would imagine much of this stuff has a flame retardant value. Much of it may smoke but would not actually catch on fire. It makes sense. Of course, anything will burn at a certain point.
 I would be curious about the speaker company that uses bubble wrap. Is it exposed or is they a layer of something else in front of it? Maybe things have changed

[BrianM]

The best damping material is in fact used chewing gum.  Note that this will constitute a permanent modification to your speaker cabinet.

[dorokusai]

Have you guys seen the ads on Audiogon for the audio grade "rocks" or "gravel" that you load your loudspeaker with? I love this hobby but sometimes it's just too much.

Mark

[albee]

Just recently I was thinking about an open baffle project and it struck me that possibly bubble wrap would be a great baffle covering due to the diffracting nature of all the little bubbles.  I will definitely try this one day when I get around to it.

This could be the new, "new age" egg carton acoustic fix.   

[Russell Dawkins]

Bubble wrap is what is recommended for Hammer Dynamics Super12:

http://www.diyparadise.com/hammer.html

This is the first reference I've seen to bubble wrap used this way - I wouldn't have thought it would work.

[Luigi]

I have the Hammer Super12s and tried the bubble wrap. Maybe I used the wrong stuff, and should have gone for the real thick bubble wrap, cos the thin small bubble wrap applied to the walls didn't do jack, in my opinion. I ended up using underlay behind the driver, some of that British wall damping material (forgotten its name), and Dacron fill and this seemed to quieten the cabinet reasonably.
Lately I have been using the Super12 drivers to augment the Visatons OB and they seem to do quite a nice job. They don't go that low naturally but they have a nice tone.

Anyway, the cabinet they came in is just too big. Damn coffins, my partner reckoned, and banned them from the living room.