Dampening Material for My Loudspeaker?

[pooge]

There are 3 kinds of UltraTouch,
1/ The foil backed stuff you mention, i've not seen that.
UltraTouch 4 ft. x 6 ft. Radiant Barrier - 30000-11406 at The Home Depot
It is only 3/8". If the foil is facing the wall i don't see any issue except heat transfer

2/ a 1/2" felt with a very thin black cloth "lining" on the back. This is the stuff we use a lot of for lining vented boxes. The lining is an aid to gluing it to the box and scribing shapes with a felt pan. This isn't on the web site and Bob & i may have found a localized stash of new-old-stock. I just got 1 of the last 3 200' rolls (800 ft^2) the distrib had and it had a 2005 inspection code. Bob sells it in more diy-friendly quantity.

3/ 3 1/2" and 5 1/2" wll insultion, comes in bats like fiberglass insulation. We bought a bat of 3 1/2". We use it for volume fill (ir microTowers). This would be the choice for a sealed box Gary Pimm uses it in has Hartley Boffle like, open back boxes.
Bonded Logic - Natural Cotton Fiber Insulation

The stuff at Home Depot i was suggestion turns out to be something different, made od cellulouse. No idea about this.

Enuff people start going in and asking for #2 & 3, we may make a small dent. But the amount we use in a speaker compared to insulation a house...

dave

Home Depot has the denim type, but only in two inch thickness, and by mail only.
http://www.homedepot.com/Building-Materials-Insulation-Fiberglass-Free/h_d1/N-5yc1vZbvev/R-202709974/h_d2/ProductDisplay?langId=-1&storeId=10051&catalogId=10053

Never heard of cellulose in bats. Only loose fill.

 

[Loren42]

Actually, for damping one needs a resistance.

Boys, boys. It's a floor shine and a dessert topping.

You need a spring to dampen and some mechanism to convert mechanical energy into heat to perform the dampening. 🙂

 

[pooge]

Boys, boys. It's a floor shine and a dessert topping.

You need a spring to dampen and some mechanism to convert mechanical energy into heat to perform the dampening. 🙂

some mechanism to convert mechanical energy into heat = resistance

The "spring" is what you are trying to damp with the resistance.

 

[Loren42]

The "spring" is what you are trying to damp with the resistance.

Yes, but without the spring what have you to dampen? 🙂

 

[WithTarragon]

some mechanism to convert mechanical energy into heat = resistance

The "spring" is what you are trying to damp with the resistance.

--------------------------

Yes, putting your finger on the spring will dampen its vibration.

So can we get away from this silliness that putting fluffy fiberglass is "damping" the cabinet vibration. It is not. It is absorbing sound and perhaps making the cabinet back volume "seem larger", but it is not (realistically) damping vibration of the cabinet.

That is why the OP was asked whether he actually meant "damping" or "absorbing". I realize that it is a pet peeve of mine, but why does everyone insist on calling anything and everything you do to a cabinet: "damping".

Adding fluffy fiberglass and gluing tiles to the panels are two very different things and meant to tackle very different problems.

 

[speaker dave]

The OP was asking about damping the insides of his speaker. By that I took it to mean damping the internal acoustical resonances rather than tackling any particular cabinet wall resonances. Certainly fiberglass and felt products are very good at damping internal acoustical resonances.

David S.

 

[Loren42]

--------------------------

Yes, putting your finger on the spring will dampen its vibration.

So can we get away from this silliness that putting fluffy fiberglass is "damping" the cabinet vibration. It is not. It is absorbing sound and perhaps making the cabinet back volume "seem larger", but it is not (realistically) damping vibration of the cabinet.

That is why the OP was asked whether he actually meant "damping" or "absorbing". I realize that it is a pet peeve of mine, but why does everyone insist on calling anything and everything you do to a cabinet: "damping".

Adding fluffy fiberglass and gluing tiles to the panels are two very different things and meant to tackle very different problems.

I would agree semantically with you, but adding fiberglass or a fill will absorb some of the acoustic energy and therefore prevent that absorbed energy from exciting the cabinet walls (or driver's cone) in the first place.

 

[pooge]

Cabinet walls can be effectively damped via constrained layer damping.

Two panels are sandwiched with a damping (not dampening) layer in between.
The damping layer helps dissipate motion as heat.

There are some products used for drywall that may be useful.

http://http://www.quietrock.com/soundproof-products/damping-glue.html

QuietGlue Pro Lowest Cost Soundproofing Glue

 

[pooge]

I would agree semantically with you, but adding fiberglass or a fill will absorb some of the acoustic energy and therefore prevent that absorbed energy from exciting the cabinet walls (or driver's cone) in the first place.

Stuffing won't absorb much at low frequencies where panels may be excited the most.

 

[Cal Weldon]

The air is the spring.

Stuffing won't damp anything in the lower frequencies.

 

[planet10]

Note: For damping, one uses fiber. Dampening requires a water hose.

That discussion has occured before. Ended when someone pointed to a disctionary entry and both terms can be used interchangably.

dave

 

[planet10]

cellulose is a natural substance that is...

In every plant. Which plant, how it is processed etc can turn it into many things (including plastic)

dave

 

[planet10]

Wow, a lot of misunderstanding so far.

You can damp the cabinets or you can damp the air space. Mechanical or acoustic energy respectively to heat.

My take was that the OP was asking about air space damping.

Damping the air space has only a small effect on damping the cabinets as the acoustic energy falls with the square of the frequency and the air space dampings effectiveness decreases with frequency.

A spring is not a damper, it is an oscillator. It is the vibrating air in the box or the vibrating cabnet walls that we are trying to damp.

dave

 

[Loren42]

Damping the air space has only a small effect on damping the cabinets as the acoustic energy falls with the square of the frequency and the air space dampings effectiveness decreases with frequency.

dave

Yeah, but these are simply vocal monitors for a stage, not full range HiFi speakers. So, it really isn't that critical for the musician to get their job done. Just stuff it with fiberglass or poly.

 

[Cal Weldon]

or rockwool or an old sleeping bag or pillow

 

[Loren42]

or rockwool or an old sleeping bag or pillow

I've seen socks, underwear, you name it, fall out of some cabinets after opening.

For some reason, all the socks were left socks.

 

[Dave Jones]

That discussion has occured before. Ended when someone pointed to a disctionary entry and both terms can be used interchangably.

dave

The last dictionary to prescribe proper ("standard") usage was the 1957 Merriam Webster. Dictionaries today simply describe popular usage without regard to correctness. To get a "ruling" these days, one must consult a style guide.