2 X 12 cab design question

[wiseowl]

I want to redesign my 2 X 12 cab to make it more square in design, ideally 2' square ish. I was thinking of the 2 speakers mounted on the diagonal, see the attached sketch for clarification. (Excuse the crap sketch.)

I have a G12H30 and a Vintage 30 to fit in the cab.

Wood work is an uphill job for me, so before I start I'd like to confirm that there's nothing fundamentally wrong with what I'm planning. Suggestions as to whether closed or open back would also be welcomed.

Thanks

Martin

[ChrisU]

There's nothing wrong with that. Here's a pic of my versions. Both cabs are, (outside measurements) 645mm x 645mm x 300mm with the depth of the angled cab top reduced to 255mm. They have a bracing strut from the centre of the baffle to the rear panel to avoid boomy resonance. Material is 12mm Birch ply.
http://smg.photobucket.com/albums/v173/ ... estak1.jpg

[drew]

http://www.trinityamps.com/phpbb/viewto ... c&start=13

[zaphod_phil]

Generally, perfectly square speaker cabs aren't recommended, as they're more likely to sound boomy due to resonances. You will notice that the Hiwattish-style 2X12 cab posted in that last link by Drew isn't quite square. Having speakers mounted off centre also helps prevent boominess.

[wiseowl]

Thanks for the photo's showing your cabs. Given Zaphod's comments below :-

Generally, perfectly square speaker cabs aren't recommended, as they're more likely to sound boomy due to resonances.

I'm wondering how Chrisu's sound, do you have any clips?

Also, for the sake of argument, aren't most commercial 4X12 or 4X10 cabs essentially square? Is it purely down to the number of drivers or is there something I'm missing (Probably!)?

Edited to add: Does the square design have any, or as much effect if the cab is open backed?

Cheers,

Martin

[jaysg]

I think you'll find that most straight 4-x" cabs are off by an inch at least. Here's old school:

[zaphod_phil]

Like jaysg said, I think you'll find that most commercial 4 X12s and 4 X 10s aren't quite exactly square, even if they look squarish to the eye. Also the speakers aren't mounted dead in the center of the cab - which would be hard to do anyway. Generally the Golden Ratio is recommended as being best to use for the form factor of speaker cabs, although that doesn't always happen in practice.

[ChrisU]

The first ones I made were angled cabs, there was a bit of resonance or boominess around the low E or D - can't remember now, but I fitted a brace front to back which stopped it. Later on I got the opportunity to see inside the Marshall equivalent and theirs had the same bracing as mine. When I made the straight 2 x 12 I didn't even test it without a brace I fit them as a matter of course. I have sold quite a few now to semi pro guitarists and have had no complaints whatsoever. They have all used a pair of G12H 30's. No brace is needed if its open backed but all my sales have been for the closed version.

[wiseowl]

Thanks again for the comments.

I looked into the dimensions of some Marshall cabs and found that one model is only 25mm different between width to height. It's interesting that this small amount makes a difference and I will be modifying my design accordingly.

I'm familiar with the golden ratio, it appears throughout art and architecture and even within nature I believe. However, for this design I want the 1/2 stack look and have been considering building a 4 X something but decided I liked the sound of my 2X12 enough to stick with them.

If I go closed back I'll look into bracing the back.

As always thanks for the input, there's a heck of a lot of knowledge and experience here. I hope to be able to give some thing back when I get more experienced.

Cheers

Martin

[StarGeezers]

You know, if you wanted a perfectly square cab for appearance , you could put a small baffle at the top or bottom inside to change the inner dimensions... For a practical application, make a place to store your speaker cords...in the "wasted " space...

[ChrisU]

You know, if you wanted a perfectly square cab for appearance , you could put a small baffle at the top or bottom inside to change the inner dimensions... For a practical application, make a place to store your speaker cords...in the "wasted " space...

Or angle the baffle.

[str82hvn]

Thanks again for the comments.

I looked into the dimensions of some Marshall cabs and found that one model is only 25mm different between width to height. It's interesting that this small amount makes a difference and I will be modifying my design accordingly.

I'm familiar with the golden ratio, it appears throughout art and architecture and even within nature I believe. However, for this design I want the 1/2 stack look and have been considering building a 4 X something but decided I liked the sound of my 2X12 enough to stick with them.

If I go closed back I'll look into bracing the back.

As always thanks for the input, there's a heck of a lot of knowledge and experience here. I hope to be able to give some thing back when I get more experienced.

Cheers

Martin

Hi Martin,

I had cabinet made of 1" pine with a 1/2" baffle that is amazing with my 18 Watt.

http://www.trutonecustom.com

The work was all first class and it sounds a lot like what you are building. the final dimensions were. 28.5" x 28.5" x 10" and it is not booming or anything but SWEET.

Good luck,


str82hvn