dynamat on the inside of box....

[waNtsumBuMP 10+ year member]

since everyone is using it to seal up the trunks/hatches, and it usually helps the number increase, what would the effect be of puting dynamat, or peal and seal on the inside of the box.... i think it would look preaty **** cool too....

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[nosaj070 10+ year member]

Erm, well first no one can see the inside of the box, second, sound deadening is used to keep sound waves in, and to rid of rattles, two things the mdf doesn't have a problem doing. All it would do is take up space.

 

[Naxis2k1 10+ year member]

Erm, well first no one can see the inside of the box, second, sound deadening is used to keep sound waves in, and to rid of rattles, two things the mdf doesn't have a problem doing. All it would do is take up space.

GOOD ANSWER! //content.invisioncic.com/y282845/emoticons/handclap.gif.0c301076f534e244f0460706894f19e0.gif

 

[waNtsumBuMP 10+ year member]

yeah that was exactly what i was thinkin, the only reason i was askin, was becuz on pimp my ride, they always put dynamat on the indisde of there plexiglass boxes, but i didnt know if it was just for looks or not.....

 

[DBfan187 5,000+ posts]

Aso, if its ported. It will raise your tuning.

 

[tommyk90 5,000+ posts]

Aso, if its ported. It will raise your tuning.

Actually, i think if it takes up space it would lower your tuning.

Smaller box and the same size port=lower tuning. No? //content.invisioncic.com/y282845/emoticons/confused.gif.e820e0216602db4765798ac39d28caa9.gif

 

[Moe Lester 10+ year member]

Actually, i think if it takes up space it would lower your tuning.
Smaller box and the same size port=lower tuning. No? //content.invisioncic.com/y282845/emoticons/confused.gif.e820e0216602db4765798ac39d28caa9.gif

if your port size/length is constant, but the box size decreases, the tuning goes higher.

 

[tommyk90 5,000+ posts]

if your port size/length is constant, but the box size decreases, the tuning goes higher.

Hmm, i dont know why i thought otherwise. Oh well.

 

[idiot 10+ year member]

Isn't this useful if the box is made of fiberglass rather than MDF, though?

 

[squeak9798 5,000+ posts]

yeah that was exactly what i was thinkin, the only reason i was askin, was becuz on pimp my ride, they always put dynamat on the indisde of there plexiglass boxes, but i didnt know if it was just for looks or not.....

First off, do not base your stereo design/choice off of what you see them do on "Pimp my POS". They appear to know about as much as ass hair about stereos.

But, they plexi isn't nearly as strong as MDF. You need really thick plexi to get much strength from it (which isn't cheap), so they are probably using some fairly thin/flexible crap, and so they use the sound deadening to help reduce some resonance problems with the box.

 

[squeak9798 5,000+ posts]

Isn't this useful if the box is made of fiberglass rather than MDF, though?

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.

 

[RattlinStratus 10+ year member]

They do that to the fiberglass because it sometimes is prone to rattling. If you have a fiberglass box you are most likely not going for SPL, so they are probably going for show or SQ, and the box is sealed so when they put the dynamat on it, it keeps it from vibrating and it may actually help to stiffen the glass.

 

[RattlinStratus 10+ year member]

Squeak is right fiberglass can be as strong as the mdf. They probably use that sound deadening stuff to compensate how shitty their boxes sound and how bad they rattle.

 

[idiot 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.

So is there no reason to spray rubberized undercoating inside a fiberglass box, or line the sides with modeling clay, or apply deadening material, or any of a thousand other ways to manipulate box resonance, if it was built properly? Because I’ve seen all of these done and recommended.

I’m building my first glassed box, and don’t really know if it’s constructed properly or not (due to lack of experience). I will have finished putting about 10 layers of Bondo brand mat down soon, and it still will just barely be ¼” thick (which many people consider too thin, apparently)… so I’m not sure if I’ll have to be one of those who will have to slap something on the insides to compensate for poorly-built box. This was why I was wondering.

 

[squeak9798 5,000+ posts]

So is there no reason to spray rubberized undercoating inside a fiberglass box, or line the sides with modeling clay, or apply deadening material, or any of a thousand other ways to manipulate box resonance, if it was built properly? Because I’ve seen all of these done and recommended.

It completely depends upon how thick you make it. If you don't have enough layers of 'glass, then sure it's going to be weak. And as I mentioned, you can lay ropes and such inbetween the layers to strengthen the 'glass. If anything, bracing it would be the best way to go.

The spray-on undercoating I seriously doubt will be heavy enough to do anything. But, Read This, pay close attention to Dan Wiggin's posts, and it should give you a good idea of the best ways to go about it. The thread is aimed towards kickpanels, but the same concepts can be applied to sub enclosures. Notice what he says about what is required to change the resonance