Bubble Wrap as Speaker Damping/Dampening Material

NagysAudio · « **on:** 18 Mar 2010, 05:39 pm »

I brought this subject up before, but I think it's interesting enough to do it again. I've used virtually every material available for speaker dampening (wool, fiberfill, foam, BlackHole 5, fiberglass, Acousta-Stuff, etc.), but nothing ever worked better than simple bubble wrap.

For example, in a ported design I line the walls with 1/2" self adhesive acoustic foam and then make a huge roll of bubble wrap and stuff the rest of the box with it.

I'm just curious to know if anyone else has experimented with bubble wrap an what are your thoughts about it.

For all the new speaker builders out there, give bubble wrap a try, it's truly amazing on what it can do to dampen the sound waves. Nothing else really can compete in my opinion.

avahifi · « **Reply #1 on:** 18 Mar 2010, 07:43 pm »

It would seem to me that all the little sealed bubble wrap bubbles would significantly reduce the interior volume of the speaker cabinet. That would of course have a sonic effect, but perhaps not the desired one.

Also, each little springy soft pillow full of air would have a resonant frequency, but likely pretty high in comparison as to what the speaker design requires.

However, if you play the Telarc 1812 Cannons REALLY LOUD with a speaker full of bubble wrap, it might add a great 21 gun salute to the performance as all the bubbles pop.

Best regards,

Frank Van Alstine

jtwrace · « **Reply #2 on:** 18 Mar 2010, 07:46 pm »

Nagys

I'm confused on how the bubble wrap would allow the sound waves get "absorbed" into the wrap. It seems to me the sound waves would just "bounce".

Can you explain?

gerald porzio · « **Reply #3 on:** 18 Mar 2010, 08:14 pm »

If you could get the bubble wrap to undergo osmosis as the back waves impact it, you might be nominated for a Nobel Prize. If not, keep your day job.

turkey · « **Reply #4 on:** 18 Mar 2010, 08:15 pm »

Quote from: jtwrace on 18 Mar 2010, 07:46 pm

Nagys

I'm confused on how the bubble wrap would allow the sound waves get "absorbed" into the wrap. It seems to me the sound waves would just "bounce".

Can you explain?

I suspect there would be some absorption as the sound wave passes through the mass of air-filled cells. I'm not sure how much there would be, and I suspect it wouldn't work as well as the mechanical movement of fibers such as happens with polyfill, where energy is actually expended moving the fibers (and then becomes heat).

If each cell were actually rigid, so that you couldn't easily compress the cells, you'd reduce the volume of the enclosure by quite a bit. Since that isn't the case, it's questionable whether this would be the effect or not.

You can think of it as if you put a rubber sheet across part of the enclosure. It would flex in and out, so the pressure in the partitioned-off part would vary as the pressure in the non-partitioned-off part varies. There are limits to the elasticity of the rubber sheet (or the plastic film in the bubble wrap case), so there would be probably be some reduction of the apparent enclosure volume. It would seem to be a rather non-linear effect too, given that neither a rubber sheet or some thin plastic film are perfectly elastic.

NagysAudio · « **Reply #5 on:** 18 Mar 2010, 09:00 pm »

The volume reduction is a non issue, as even in the most basic designs one would take that into consideration.

As far as what exactly bubble wrap does is hard to tell without experimenting/measuring. Both are time consuming and EXPENSIVE!

I suspect it could act as a diffuser, where the back wave of the speaker gets diffused evenly throughout the enclosure and into the surrounding foam.

Also, I would be interested in finding the resonant frequency of bubble wrap, so it can be determined what frequency range it absorbs and what frequency range it reflects, etc.

I don't yet have the proper lab conditions to do these types of measurements, but from at least extensive listening and long experience in building speakers, I can say that bubble wrap works wonders. Just curious to see if anyone else out there has any experience with it.

WGH · « **Reply #6 on:** 19 Mar 2010, 12:47 am »

Quote from: NagysAudio on 18 Mar 2010, 09:00 pm

Just curious to see if anyone else out there has any experience with it.

My only experience is here:

http://www.bubblewrapfun.com/assets/games/bubblePop.html

(sorry, couldn't resist)

Wayne

gerald porzio · « **Reply #7 on:** 19 Mar 2010, 12:54 am »

Where in audio did bubble wrap work wonders - other than as packing material?

NagysAudio · « **Reply #8 on:** 19 Mar 2010, 01:15 am »

I suggest some of you speaker builder out there to try it.

Oh and if anyone packs their electronics with bubble wrap, YOU are the problem for all the damaged equipment.

jtwrace · « **Reply #9 on:** 19 Mar 2010, 01:20 am »

Well, I'll admit this is one of the craziest things I've ever read. BUT I'll be interested to read what the pro speaker builders on this site say.

anyone?

gerald porzio · « **Reply #10 on:** 19 Mar 2010, 01:34 am »

Then we can find out if the bubbles need 40 to 978 hrs. of break in.

jtwrace · « **Reply #11 on:** 19 Mar 2010, 03:41 pm »

Quote from: gerald porzio on 19 Mar 2010, 01:34 am

Then we can find out if the bubbles need 40 to 978 hrs. of break in.

turkey · « **Reply #12 on:** 19 Mar 2010, 04:30 pm »

Quote from: NagysAudio on 19 Mar 2010, 01:15 am

I suggest some of you speaker builder out there to try it.

Oh and if anyone packs their electronics with bubble wrap, YOU are the problem for all the damaged equipment.

Bubble wrap seems to work fine for objects that aren't heavy. What is your objection to it?

jtwrace · « **Reply #13 on:** 19 Mar 2010, 04:40 pm »

I want to know how this came about. If my wife saw me taking out my acoust stuff (and other filling) and putting in bubble wrap I think that would put her over the edge and have me commited. Trust me, she's seen some wild things that I've done.

rollo · « **Reply #14 on:** 19 Mar 2010, 06:15 pm »

Hey guys cut Nagy a break. When and if you try his recco then comment. It just may work well.
Yes Nagy is a bit agressive but does not deserve a bashing YET that is. If we find his reccos BS than by all means fire away but please not until then. My 2 cents.

charles

jtwrace · « **Reply #15 on:** 19 Mar 2010, 06:19 pm »

Quote from: rollo on 19 Mar 2010, 06:15 pm

Hey guys cut Nagy a break. When and if you try his recco then comment. It just may work well.
Yes Nagy is a bit agressive but does not deserve a bashing YET that is. If we find his reccos BS than by all means fire away but please not until then. My 2 cents.

charles

I''m not bashing at all.

satfrat · « **Reply #16 on:** 19 Mar 2010, 06:20 pm »

Quote from: NagysAudio on 19 Mar 2010, 01:15 am

I suggest some of you speaker builder out there to try it.

Oh and if anyone packs their electronics with bubble wrap, YOU are the problem for all the damaged equipment.

I would use bubble wrap over peanuts for any light piece of audio gear. Styrofoam is a must though for speakers, heavy amps, power conditioners, etc. I dislike peanuts with a passion but bubble wrap works damn good for dacs, preamps, USB Transporters, etc.

As far as bubble wrap as a damping tool,,, I'd use it as quick as I would peanuts.

Cheers,
Robin

Barry_NJ · « **Reply #17 on:** 19 Mar 2010, 07:58 pm »

Serious question...

What size/diameter of bubble did the wrap you use have? I've seen different sizes available.

It's not that difficult to get my head around how this could/would actually function...

Each little sack of air acts as an air-spring, absorbing the back-wave, not to different from how it would absorb/dissipate impact encountered in a shipping container.

NagysAudio · « **Reply #18 on:** 22 Mar 2010, 08:55 pm »

Smaller bubbles, 1/4" - 3/8" in diameter. Not the larger bubble wrap.

gerald porzio · « **Reply #19 on:** 22 Mar 2010, 09:22 pm »

All together now, "Bubbles, tiny bubbles..............."