#1
Ive been planning on building a 212 cab to go with the amp I am currently building and while looking around at pictures of 212s I noticed that alot of 212s and 412s have a piece of wood in the center and others dont. Whats that for? Do you recommend I make a cab with or without it?

Marty Friedman is GOD!

curently in a SEX MACHINEGUNS and X JAPAN phase AND Galneryus AND Anthem phase

damn J-Metal, why you so awesome

My Gear:

Schecter Hellraiser V-1 fr
Ibanez RG321mh
Fender GDC-200sce
Peavey Vypyr 30 w/ sanpera 1
#2
IF you build a 4x12 without that "brace," two things will happen. One, you'll find yourself with a nasty resonance in the audible range at a frequency associated with a multiple of the diagonal (in inches) of the big back panel. Probably the same thing with a 2x12.

In addition, a single panel of non-braced wood will "oilcan." When the speaker cones move back, the air pressure inside the cabinet increases and the panel of wood wants to bulge outward. When they move forward, the air pressure sucks that panel into the cabinet. This ultimately robs the speakers of power and increases the chances of a really unpleasant buzz.

The brace is an attempt to reduce both problems. A better solution is to put better bracing on the back panel (and the front, for that matter) to make both stiffer and reduce the distance over which a resonance can build up. Here's an example of a speaker cabinet designed to handle nearly 1500W. It's actually made of 1/2" ply, but the bracing design allows it to act like 1" plywood without in terms of stiffness, impact resistance, anti-oilcanning, etc.:

#3
I see, thanks. that helped alot.
Marty Friedman is GOD!

curently in a SEX MACHINEGUNS and X JAPAN phase AND Galneryus AND Anthem phase

damn J-Metal, why you so awesome

My Gear:

Schecter Hellraiser V-1 fr
Ibanez RG321mh
Fender GDC-200sce
Peavey Vypyr 30 w/ sanpera 1
#4
I have another question regarding this. I imagine the oilcanning and resonance has alot to do with the backpanel being closed. so is this still an issue if the back panel is open or half open?
Marty Friedman is GOD!

curently in a SEX MACHINEGUNS and X JAPAN phase AND Galneryus AND Anthem phase

damn J-Metal, why you so awesome

My Gear:

Schecter Hellraiser V-1 fr
Ibanez RG321mh
Fender GDC-200sce
Peavey Vypyr 30 w/ sanpera 1
#5
That all depends on the size and tuning of the box. Generally an open back cabinet takes a lot of load off the front baffle. Best sounding cab is always the one that does not flex.
"Your sound is in your hands as much as anything. It's the way you pick, and the way you hold the guitar, more than it is the amp or the guitar you use." -- Stevie Ray Vaughan

"Anybody can play. The note is only 20 percent. The attitude of the motherfucker who plays it is 80 percent." -- Miles Davis

Guthrie on tone: https://www.youtube.com/watch?v=zmohdG9lLqY
Last edited by Cajundaddy at Sep 15, 2014,