How Essential Is Fiberglass Resin/PolyFill?

[KJLiberty]

I've built a box for my two 10" subs. For two sundown e10d4s. 2.1cubes to be tuned to 35hz by 3" precision port for those who wanted to know. Since I'm using a precision port so I didn't think I needed to use fiberglass resin or another sound dampening material as its not a slot port type enclosure. Then I was reading about enclosures in general on the12volt.com and it spoke very highly of using a type of sound dampener like fiberglass resin because it maximizes output.

Should I get some fiberglass resin or poly fill? Is it that necessary? And I assume PolyFill is cheaper so can I use some adhesive and glue it down to the walls of the box to keep it from exiting the port? How much?

[heebs 09gts]

For the fibreglass resin, are you talking about mixing up a batch and just "painting" the inside of your box?

[bhsdriller]

don't worry about doing any kind of fiberglass work on that box....wouldn't notice a difference
as long as it has good joints and plenty of glue it's fine

Edit: you're saying fiberglass resin, are you talking about fiberglass insulation? That's what I thought since you're also mentioning polyfill

[wickedwitt]

It is so essential, I have exactly 0 of it in my box.

[KJLiberty]

For the fibreglass resin, are you talking about mixing up a batch and just "painting" the inside of your box?

yes painting it

don't worry about doing any kind of fiberglass work on that box....wouldn't notice a difference
as long as it has good joints and plenty of glue it's fine

Edit: you're saying fiberglass resin, are you talking about fiberglass insulation? That's what I thought since you're also mentioning polyfill

yeah i was very generous with glue and have more if needed. i was talking about the kind you paint on.

[keep_hope_alive]

resin and fiberglass are used to stiffen an enclosure and make it air-tight. MDF is porous by design, which means it's a bit lossy as-is.

polyfill is not near as effective as fiberglass batt insulation or acoustic insulation/sound batts. but for a vented enclosure - you don't want to block the pathway for the port or you create an aperiodic enclosure.

for my home subs, i pack the ports with an acoustic material to make it more aperiodic - it tames resonance and impedance rise. i wouldn't do it for car subs where high output is desired. i have ran aperiodic in a car when SQ was desired.

none of these provide "damping".

[KJLiberty]

Oh I see. So I'm ok where I'm at then. Thanks

[neonblack]

I think he's talking about some people who coat inside of box with resin for extra stiffness. But that's not necessary if you use 3/4" MDF and brace the joints.