cabinet design....

[freakk guitarist]

hey guys, im looking for some information on cabinet design theory regarding interior dimensions/volume/rigidity and how it effects feel/tone of the cab. i know its possible to tune a cabinet to have slight boosts or cuts in fequency responce by adjusting the interior dimensions... my questions is now how would i... someone with

no engineering/mathematics background go about figuring out the best

interior dimensions, "q" and overall interior volume of a cabinet? say

in the intrest of "tuning" so the lowest fundamental note is D, or C

instead of E. also, am i going to run into any problems with phase cancelation within the cabinet? or isnt the whole point of a sealed cabinet to act as a spring for the backs of the speakers..or does phase still still matter alot inside the cab.

 

 

ian

[freakk guitarist]

bump?

[chris_d]

If i recall correctly, Weber VST (tedweber.com) has or had some form of cabinet calculator that you could just plug your numbers into. You will need to have various specific info on the speakers you intend to use, and all those kind of fiddly bits, but it might help anyhow.

EDIT: Found it. Here:
http://www.webervst.com/spkrcalc/closed1.htm

-chris

[teemuk]

http://www.linearteam.dk/default.aspx?pageid=winisd

[newholland]

 

hey guys, im looking for some information on cabinet design theory regarding interior dimensions/volume/rigidity and how it effects feel/tone of the cab. i know its possible to tune a cabinet to have slight boosts or cuts in fequency responce by adjusting the interior dimensions... my questions is now how would i... someone with no engineering/mathematics background go about figuring out the best interior dimensions, "q" and overall interior volume of a cabinet? say in the intrest of "tuning" so the lowest fundamental note is D, or C instead of E. also, am i going to run into any problems with phase cancelation within the cabinet? or isnt the whole point of a sealed cabinet to act as a spring for the backs of the speakers..or does phase still still matter alot inside the cab. ian

 

 

well {censored}.. lemme try to address some of this stuff.

 

i think you might have something sort of messed up about this theory- you wouldn't WANT to have your box 'resonate' at a particular frequency to boost it... that's not necessarily a pretty occurrance! you usually tune your box LOWER than the Fs (resonant frequency) of the driver precisely so you DON'T get resonances! you can add a LITTLE by allowing box tunings to get close.. but, it would sound really silly to let it add, say 10db at a certain frequency.. its' all a balancing act of variables. theres great freeware programs available, such as steve ekblad's site, or speaker workshop, or WinISD (teemuk posted above!) (freeware).

 

phase cancellation DOES occur within sealed boxes-- but typically, that's why you use T/S parameters to help you tune the box. you can't STOP phase cancellation-- it's part and parcel of SOUND anyhow.. in a live space-- you're ALWAYS hearing the partial effect of phase cancellation anyhow... such is the nature of soundwaves! you just have to do your best to live WITH it-- and it's typically not that fussy of an undertaking with only one driver OR several LIKE drivers wired together without a crossover... multiple dissimilar drivers is when it gets tricky, because L/C filters alter phase angles, and you're worried about SUMMING. that's another issue... dont' worry about it here! guitar cabs are blissfully simple in that regard!

 

the only time you'd really worry about phase with a single driver system (all drivers receiving the same signal), is with a ported cab. this might be where you're getting confused. basically- a ported cabinet reflects the backwave (by definiition, 180 degrees outa phase) of speakers to reinforce bass through the port for external reinforcement. if you're ported incorrectly (the tuning is too high, or too low).. you CAN end up with REALLY wierd frequency responses.. but again.. if you're looking at sealed boxes-- not a problem!

 

anyhow-- try messing around with those freeware programs! good stuff to be found.. and you'll learn a lot about cabinets altering the drivers. celestion IS NOT good about providing ALL necessary t/s parameters.. but eminence is great about it-- so their website is a great place to start too.

 

good luck!