mechanical noise caused by 'inefficient' box size...

[d audio 450 10+ year member]

hey- got a question-

the box i originally built was to jl's specs and the thing sounded beautiful with no problems, like a lil over 1.8cuft i think...

i chopped a corner of the box off to fit it in my car better now that i have multiple amps to worry about, fans, crossovers and a powermeter i really needed the room.

problem is that now when i really crank the son of a b1tch, it falls prey to some sort of mechanical distortion, and it sounds a lot deeper than clipping, but softer than any 'noise'-like distortion ive ever heard....i know that all of jl's subs, even the w0's have the ability to sound absolutley amazing, as the w7's have the ability to sound like sh1t. my experiences with the whole line of jl's subs has made me beleive that the only factor at play (besides the amp obviously) in this mechanical type of distortion is the size of the box.....

i have heard some things that dont make sense and some things that do make sense about damping in sealed sub boxes......and what i wanna know, is can I really soften, or kill that sound by adding polyfill and what not? is it possible that my box is housing standing waves? (i thought that the wavelength of a 100hz tone was more than a few feet or something tho...) i must get rid of this sound, and it'll be while before i can rip everything outta the trunk to build a new system setup, so if anyone knows of any magical tricks or antics to combat the true evil of mechanical distortion, then please, do tell!

thanks for any help

-pat

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[theCybe 5,000+ posts]

Now that you've chopped part of the box off, what shape is it? Are the borders of the box symmetrical in relation to the woofer?

 

[tRiGgEr 5,000+ posts]

Chopped sounds like you left a hole lol.

So you made the box smaller than recommended. Polyfill is a solution. In a ported box it will need to be anchored down some how...

 

[d audio 450 10+ year member]

box's shape: picture a square with 2 corners chopped off to form a 7th plane.

no, i havent left a hole, man......wouldnt that **** if i did though....

so you're sayin polyfill will help?

thanks

-pat

 

[btnhfan 5,000+ posts]

What did you do to re seal it?

Are you sure its airtight?

 

[d audio 450 10+ year member]

i spent many hours assuring that once the woofer went in, there was no air gettin in or out....lots 0f glue, screws, and elbow grease.

but what about more damping?

-pat

thx again

 

[btmorris972 10+ year member]

try some polyfill.