Ohm's

[Bill-Murray]

What's the difference between 16 and 8 ohms?? Because I'm going to be building a marshall 4 X 12 clone pretty soon, with 25W greenbacks. I wanted to know which one would be better.. I'm going for a hendrix, jimi page, pete townshend type thing. Thanks, and yes I will have my earplugs ready.

[silvertonessuckbutigotone]

if I'm not mistaken you want the lowest possible. That said, you can't have an impednece lower than the amp your using it with. If you wanted 4 ohms, you could take 2 8 ohm speakers and wire them in parrallel. You want o match or have more impedence in your cabinet than the amp.

that is only for solid state amps. for tube amps you NEED the same impedence. if your tube amp is 4 ohms, you need four ohms, if its 8 you need 8, etc. for more info on speaker cabinets go here and read up. http://www.duncanamps.com/technical/speaker_cab.html

[westhemann]

you ALWAYS want to match the impedances

[silvertonessuckbutigotone]

a solid state amp will still drive a cabinet with a higher impedence but it won't sound as good, thats why I said as low as possible without getting below the amps impedence.

[Bill-Murray]

Oh, it's gonna be for a tube amp. Can't you build a switch so you can switch it from 8 to 16 as you please?? Cause it's gonna be 1 of the 2.

[Bill-Murray]

Okay, I'm gonna go with celestion g12h 12" speakers in my 4 X 12 I'm going to build. I'm still unsure which ohm speaker I should get. You guys say 8 is better?? Why?? And does anybody have any material about building a 4 X 12 like the 60/70's marshalls?? Thanks

[lovekraft]

What's the output impedance of your amp? That's what you need to match.

As for Marshall style 4-12 cabs, a simple sturdy, well-braced rectangular box fairly close to the size of a Marshall 1960B made from 3/4" void-free plywood will sound great. I don't remember those dimensions right off hand, but it's about 28"x28"x13". You don't have to be really precise, but you're going to have to build it solid, or it'll buzz and rattle when you crank it.

[Paul Marossy]

Can't you build a switch so you can switch it from 8 to 16 as you please??

Only if your output transformer has an 8 ohm and a 16 ohm tap...

[Bill-Murray]

I think I'll just go with 16 ohms, because I'm gonna get a plexi head eventually, can't afford it right now. Does anybody know what marshall made theirs out of?? Everybody says I should go with particle board, but I said I'd burn in hell before using particle board. They said pine would rattle, but I said not if I built it right. I want to do an angled cab too, so it gets a little more complicated. Nobody knows of a site with specs?? Thanks for the help so far..

[jnewman]

I think I'll just go with 16 ohms, because I'm gonna get a plexi head eventually, can't afford it right now. Does anybody know what marshall made theirs out of?? Everybody says I should go with particle board, but I said I'd burn in hell before using particle board. They said pine would rattle, but I said not if I built it right. I want to do an angled cab too, so it gets a little more complicated. Nobody knows of a site with specs?? Thanks for the help so far..

←

My favorite wood for making cabs and such is baltic birch plywood - it's stronger and lighter than MDF/particleboard, and a lot of third-party cab makers use it.

In the near future I'm going to be using 3/8" baltic birch to make a case for my built-from-scratch guitar that I haven't actually built yet .

EDIT: Like lovekraft said earlier, make sure it's voidless. A lot of people use 3/4" 11 ply voidless baltic birch for big cabs.

Edited February 27, 2005 by jnewman

[Bill-Murray]

Cool dude, so it's going to be a 4 X 12. Do you know of any schematics available, I've been looking forever. So they just use 3/4 for everything, or do they have sides thicker?? Oh and one more thing, what are the pros and cons of having an open back?? Like a closed back adds more stability, but loses some sound because it's closed??? I forgot to mention I'm using gh12 30's, so it will be 120W. Thanks dude.

[jnewman]

Cool dude, so it's going to be a 4 X 12. Do you know of any schematics available, I've been looking forever. So they just use 3/4 for everything, or do they have sides thicker?? Oh and one more thing, what are the pros and cons of having an open back?? Like a closed back adds more stability, but loses some sound because it's closed??? I forgot to mention I'm using gh12 30's, so it will be 120W. Thanks dude.

←

From what I understand, closing the back improves your bass response... I'm no expert though, and I haven't messed with cabs enough to really be able to tell you all that much.

[Bill-Murray]

Yeah, I think I'm gonna do a closed back. Does anybody know of a site with a tutorial on a cab??

[silvertonessuckbutigotone]

http://www.duncanamps.com/technical/speaker_cab.html

[lovekraft]

Dude, it's a sealed rectangular plywood box with an internal volume of slightly more than 4 cubic feet and four 12" circular holes cut in one side - it's not quantum physics.

[Bill-Murray]

Yeah, you're right, I'm just gonna slap a box together and hope it comes out alright. Thanks for the valuable input.

[crafty]

You should try using the WinISD software. It will help you determine exactly which speaker is best for the kind of box you want to build. It will also help you determine what size of box to use and whether or not to use a baffled, sealed, or open enclosure. I read about it a few years ago in Bill Machrone's column in PC Magazine and I tried it out myself at the time. Here is the link to his website which also has the links to the software manufacturer. It's shareware, so donations are optional:

Bill's Marshall Bass stack

It's funny how even a Marshall amp could be improved with something other than a Celestion.

[lovekraft]

Bear in mind that improving the frequency response of a guitar cabinet doesn't necessarily improve the sound of it - especially for high gain sounds, we rely on the speakers to roll off excessive high and low end for a classic guitar sound. A Marshall 1960B cabinet with Boston Acoustics 12"s in it may have a much improved range, but it may not sound good at all, and it most certainly won't sound like a Marshall!

[lovekraft]

I'm getting really good at double-posting!

Edited February 28, 2005 by lovekraft

[crafty]

Oh, I agree entirely. I just remember back in high school my friends use to build boxes for their car speakers and most of them sounded horrible. They just didn't have any idea how to design a good box. I was just a little concerned when Bill-Murray said he was just going to "slap something together". Even if you want to have the highs and lows attenuated, good planning and construction will help get you there. Throwing a Celestion inside a plywood box without any sort of consideration of the speaker manufacturer's recommendations is not.

[Bill-Murray]

Oh dude, I was being sarcastic. Thanks for the article, it was some interesting helpful stuff, I'll keep that in mind. I guess I'm just going to make a 1960b clone. Anybody got the measurements??