Why not adding some sound deadener inside an enclosure?

[SQBubble]

Well, I was thinking, maybe adding a couple of layers(2-3) of some second skin damplifier pro or wtv over the wood inside the enclosure and then add a pink fiberglass or some egg-like foam layer over them ...

wouldn't that help rigidity and get rid of annoying inside resonating frequencies? as it'll make each side pretty heavy enough to keep the pressure well inside the box, intact and clean.


what do you guys think of that?

discuss plz

[SteveCallas]

I've personally never experienced any resonances with my poly batting-lined sonosub

[Robert_J]

This has been brought up time and time again over the years I have been on the DIY forums and it is agreed upon that it is a waste of time. If you can search the archives at HTF, Dan Wiggins has a great explanation why it is a waste.

-Robert

[Mike P.]

Fiberglass or egg crate foam damps the resonances. Rigidity is acheived by proper bracing of the cabinet.

[avaserfi]

I am not entirely sure why it is so widely used, but I would like to point out that egg crate foam does not sufficiently dampen a cabinet. Many people use such foams on the internal areas of the subwoofers and loudspeakers and to be honest I am not sure why as in most all cases* its absorbency coefficient is very poor especially when compared effective alternatives like OC703/705 or a reasonably high density mineral board (6-8lb).

*There are some foams specifically designed to be used for acoustic dampening purposes and these generally measure far better than most other foams (think Auralex or Echobusters), but are usually still not as effective as other mentioned alternatives.

Proper internal dampening of a cabinet is necessary fully remove standing wave issues which can cause resonance as well as other possible issues.

[Mike P.]

No question there are better dampening materials. So far I've built 7 HT subs and have had no issues with resonance using egg crate foam. Although egg crate foam may have a poor absorbency coefficient, it does do the job.

[ISLAND1000]

SQBubble wrote:

and get rid of annoying inside resonating frequencies?
discuss plz

"annoying" What're those?

Yes, add sound deadening. Anything that reduces, absorbs, or lowers the level of reflected sound INSIDE the enclosure theoretically helps, including bracing. Ported, IB, LLT, etc. subs only use the "tuned" and 'Q' function of the enclosure.