Box Building Specs

[vinnym86]

I've got 2 12" Eclipse subs that i'm going to build a box for, but i'm not sure of what calculations i need to make to get the volume I need. I was thinking of going ported, but realized that sealed will give me a better SQ?
I haven't gotten supplies yet, but based on measurements i can start. If anyone knows what formulas to use, or if they have some program that will calulate it, it'd be a great help. speaking of programs, are there any freewares out there that'd help me? thanks in advance!

Here are the Specs of ONE SW6123.4

Free Air Resonance (Fs)___ 29Hz

Total Driver "Q" (Qts)_____ 0.68

Vas (ft^3)______________ 2.4

X-Max Linear (1way)______ 0.81in

Freqeuncy Response (Fr)__ 29-2500Hz

Driver's Volume (ft^3)_____ 0.111

EDIT: I've found a nice box volume calculator on bcae1. it also says that my subs would better perform in a sealed enclosure. OK, but i don't have the manual (got em off eBay) and i can't find the recomended box volume! does anyone know a formula to get a good box volume for these subs?

[superchuckles]

according to your own data, the speakers are rated using 2.4 cubic feet of air space - go with that. use 3/4" or 1" MDF for your box. a table saw makes the cleanest & most square cuts, which when glued & screwed (i use drywall screws) -- i can park a 4x4 on any enclosure i've made without worry of breaking at any glue joint (though 3/4 mdf might break but doubtful, since i'd only use it on smaller boxes). make sure you use MDF & not that crap made for roofing - MDF=Medium Density Fiberboard and does not look like big chips of wood - it's made of fine bits of sawdust that are more like dust than larger pieces of wood. reason for using this is - MDF is not only denser & seals better, but MDF doesn't have a "built in" resonance frequency like solid wood would (or roofing sheet). i'd recommend putting an isolation wall in your box in between the two speakers, even if you're running your speakers in parallel on a mono amp. reason? every speaker has small differences, & putting the isolation wall in keeps down distortion created when one woofer pushes harder than the other in the same box. seems like it might be trivial to some people, but what they don't realize is that that extra push can force one speaker too far causing distortion & premature speaker wear - eventually a blown speaker can/will result. good luck with your box - & good job on reasearch! i can't count the amount of times people have tried ported boxes & been dissapointed because they didn't really understand the dynamics necessary to get a benefit from porting (or how the box really needed to be designed).

[vinnym86]

Originally Posted by superchuckles

according to your own data, the speakers are rated using 2.4 cubic feet of air space - go with that. use 3/4" or 1" MDF for your box. a table saw makes the cleanest & most square cuts, which when glued & screwed (i use drywall screws) -- i can park a 4x4 on any enclosure i've made without worry of breaking at any glue joint (though 3/4 mdf might break but doubtful, since i'd only use it on smaller boxes). make sure you use MDF & not that crap made for roofing - MDF=Medium Density Fiberboard and does not look like big chips of wood - it's made of fine bits of sawdust that are more like dust than larger pieces of wood. reason for using this is - MDF is not only denser & seals better, but MDF doesn't have a "built in" resonance frequency like solid wood would (or roofing sheet). i'd recommend putting an isolation wall in your box in between the two speakers, even if you're running your speakers in parallel on a mono amp. reason? every speaker has small differences, & putting the isolation wall in keeps down distortion created when one woofer pushes harder than the other in the same box. seems like it might be trivial to some people, but what they don't realize is that that extra push can force one speaker too far causing distortion & premature speaker wear - eventually a blown speaker can/will result. good luck with your box - & good job on reasearch! i can't count the amount of times people have tried ported boxes & been dissapointed because they didn't really understand the dynamics necessary to get a benefit from porting (or how the box really needed to be designed).

heh, i didn't think ne one would post to this one. thnx for ur help. but i have just found online manuals for my subs, which recomend 1.9cu.ft./sub. i'm gonna build it to those specs cuz im guessing (rather hoping) they know what they're talking bout when they recomended those specs on their manual. as for material, i wouldn't use ne thing else than mdf, x'cept fiberglass (if i only had enough experience w/ it though).

one thing that i don't get, but don't think is important (could be just my ignorance) is they say: "Sealed box for single (Q=1.2) Dual (Q=1.0) (Net internal volume, filled, loss Q=7, form LEAP)" ...wtf is that?

[highteknology]

Originally Posted by vinnym86

(Net internal volume, filled, loss Q=7, form LEAP)" ...wtf is that?

i'm sure what the that means, but for some reason i don't think you need to worry about it. what it may mean, and this is a total shot in the dark, is that when it is filled, i.e. using pollyfil. who knows.

Originally Posted by vinnym86

"Sealed box for single (Q=1.2) Dual (Q=1.0)

the reason the dual volume is smaller is because it's probably taking into account both magnets and everything in a dual inclosure, NOT using a divider. i would just build it to the single specs and include a divider.