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4x12 idea


Fixr1984

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I've been toying with the idea of rebuilding my 4x12 cab.

I keep hearing people asking the difference between closed and open backs.

I understand that each one has its place but what if you had both.

What I plan to do is build the cabinet to the aproximate size of a normal cab but to have

a panel inside separating the top and bottom speakers making the bottom a sealed cab. Then the top would

be an open back. I hope that makes sense.

What do you think?

Pros/cons?

 

 

Jason

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I've been toying with the idea of rebuilding my 4x12 cab.

I keep hearing people asking the difference between closed and open backs.

I understand that each one has its place but what if you had both.

What I plan to do is build the cabinet to the aproximate size of a normal cab but to have

a panel inside separating the top and bottom speakers making the bottom a sealed cab. Then the top would

be an open back. I hope that makes sense.

What do you think?

Pros/cons?

 

 

Jason

 

 

 

It is a good idea, I have actually built a couple of cabs that way, and the results were good. Just make sure you have the open back part on top.

 

 

EDIT: I paint all of the cabs I build black inside. For the 2x12 the jack always rests on a non removable backplate... and the rest of the back is removable... that way if you want to alternate between using it closed and open, you have a cab that looks *** great both ways.

 

 

Looking at deepblues' picture I remember a cab I made a couple of years ago (havent seen her since)... the thing was a 4x12 closed back, and the jack was positioned on the upper side of the back woodpiece. Now, the special thing comes here... errr... maybe I should tell you via PM... you don't plan on patenting this or building them commercialy do you?

 

The back hass two sections... the lower one is screwed like a normal 4x12 cab's the upper part has the jackplate and if you wanted, you could open it, but it opened and had some rails that let the owner put it horizontal inside the cab, so that piece of wood would act as the upper piece of the lower 2x12 cab... leaveing the jackplate horizontal and the upper part as a separate 2x12 open back.

 

Don't know if I have made myself clear... I guess I should have the blueprints somewhere, but would be lying if I toold you I can find them this year (was a couple of years ago and have bought more than 5 computers each with more than 1000 hard drive space, and I dont really know how the file was called... ). But if you want any help you can always PM me...

 

Hope this was of any help.

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Watch out for the speaker's compliance.

 

Closed-back loads the speaker - so you can get away with lower compliance units for more power and a better frequency response.

 

Open backs need a higher compliance speaker to prevent the coil just flying out (or at least to keep it controlled) under power and keep the sound good.

 

The open back dimensions are significant too as far as resonances go, because that signal from the rear interferes with the direct signal from the front, destructively at some wavelengths, constructively at others. Try and keep to the size of open-backs you like for the sound you like - stray too far and the sound will (quite predictably too) change.

 

I have reams on designing cabinets if you wanna get technical..... (which will come as no surprise to some here)

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The simple solution to the open/closed back dilemma...

 

brownback.jpg

 

This how Avatar is doing it. Has a bit more thump than a true open back cabinet, but it still has some of the open back's throatiness. I have two and love 'em.

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All excelent ideas. I think the first thing I should do before going thru

all the trouble making a cab and finding it sucks is to maybe just make a

new back for mine but with a hole similar to what Surfpup posted.

 

Surfpup: would you say that your cab kinda bridges the gap between

open and closed back? Best of both worlds maybe?

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Surfpup: would you say that your cab kinda bridges the gap between

open and closed back? Best of both worlds maybe?

 

Yes, I would say that. As I wrote below the pic...

 

"Has a bit more thump than a true open back cabinet, but it still has some of the open back's throatiness."

 

In other words... the best of both worlds.

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The simple solution to the open/closed back dilemma...

 

brownback.jpg

 

This how Avatar is doing it. Has a bit more thump than a true open back cabinet' date=' but it still has some of the open back's throatiness. I have two and love 'em. [/quote']

That's good stuff, surfpup. I use a similar cab - a Mesa 3/4 back 2x12 which is kind of the same idea.

 

2x12-3QB-bkLG.jpg

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