dynamat on the inside of box....

[idiot 10+ year member]

I've read that post before, which led to a discussion (on a different board) regarding the benefits to layering cement on the inside of a box as a mass-loading device.

But if you're arguing that matting is an insufficient means of adding mass and lowering resonance, why is sound deadening the door panels seen almost as a required action, here and on other boards? I doubt a few layers would come close to doubling the mass of the effective door panel area (I'm excluding anything above the window, which is not part of the enclosure, once covered), yet it seems to be effective (lowering vibrations merely one of many claimed benefits).

 

[squeak9798 5,000+ posts]

But if you're arguing that matting is an insufficient means of adding mass and lowering resonance, why is sound deadening the door panels seen almost as a required action, here and on other boards?

Because we can't change the construction of the door panel to better suite our needs //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif Have you ever tried bracing your trunk, or trying to build it out of thicker material? No, because it's impossible, so we have to do what we can. Whereas when we build 'glass enclosures, we can do things such as brace them and build them differently (like the rope inbetween layers thing) to stregthen them.

 

[rumydad 10+ year member]

i am doing my first glass box also and i am constructing the entire box of mdf and just glassing the front(the only side to be seen due to construction) for looks that is ok right?

 

[idiot 10+ year member]

Because we can't change the construction of the door panel to better suite our needs //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif Have you ever tried bracing your trunk, or trying to build it out of thicker material? No, because it's impossible, so we have to do what we can. Whereas when we build 'glass enclosures, we can do things such as brace them and build them differently (like the rope inbetween layers thing) to stregthen them.

I don’t deal with trunks; I have a wagon. //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

Alright, I understand what you’re saying. I guess I’ll just use some rope, then.

 

[squeak9798 5,000+ posts]

I don’t deal with trunks; I have a wagon. //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

I don't deal with trunks either. I put all my speakers (and subs) infront of the front seats //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

 

[rx7vert 10+ year member]

the rubberized undercoating inside a figerglass box helps keep the smell of the resin down.

The dynamat/peel and seel keeps the door panels and trund from flexing, and causing resonance. In physics, if you take it, you learn about mass and inertia. Basically, something with less mass has less inertia, and it is easier to move. Added mass, means higher inertia, and more difficult to move. A bare door panel is fairly thin, flexible, and light. The pressur and vibration of the speaker move it easily, causing rattles and resonance. dynamat is put on to add mass to the panel. When you add the mass, it increases the inertia, and makes the panel more difficult to move, therefore reducing rattles and resonance.

 

[plazman 10+ year member]

What, sound deadening? Fiberglass can be just as strong as MDF if the box is constructed properly. 'Glass is extremely strong when curved, and rope and such can be added to help strengthen the flat surfaces.

how would you add rope to a fiberglass box?

 

[nosaj070 10+ year member]

how would you add rope to a fiberglass box?

Resin the rope to the sides...

 

[plazman 10+ year member]

Resin the rope to the sides...

like make 1 wrap around?

any special way?

 

[rx7vert 10+ year member]

fray the end of the rope, smash it against the side of the box, apply resin, I like to put a layer of cloth around the rope, and over the frayed end.