My Somewhat Unconventional take on Ideal Speaker Cabinet Size | Warehouse Guitar Speakers

My Somewhat Unconventional take on Ideal Speaker Cabinet Size

My Somewhat Unconventional take on Ideal Speaker Cabinet Size

Every now and then I am asked a question that directs my thoughts towards cabinet dimensions.  A good one just came in to the WGS Q&A forum.  When I get to thinking, I often get to blogging.  So ... let’s talk guitar speaker cabinet dimensions!

First rule: there are no rules.  There are a plethora of "ideal size" cabinet calculators available.  Those are fine for some purposes, like for getting the most bass response in a certain frequency range out of a certain sub driver, but I personally don’t believe they have much to offer when we’re talking guitar speaker cabinets.  This is particularly true where open-back cabinets are concerned.  I just took a quick inventory, and I have 12 1x12 combos, and no two of them have the same dimensions.  Here is a quick run-down of a few notable models, all of which sound quite good in their own way. (All dimensions in inches, rough, simply a quick tape-measure reading)

My old narrow panel 5e3 tweed Deluxe: 20”x16”x8” (width, height, depth)

A late 60’s Unicord 65: 16x29x7

My 1965 Deluxe Reverb: 22x16.5x9.5

My 1983 Rivera erea Concert: 24x19.5x10.5

A Gibson GA20RVT “Gold Tone”: 24x17x10.5

Jet City JCA2112RC: 21x20x11

Bugera Vintage 22: 22.5x18.5x10.5

My Bob Burriss Boutique "convertible" 1x12 cabs: 23x17x10

It is notable that all of these, save for the Burriss cabs, are open-back to varying degrees.  The Burriss cab can be either open or closed back.  In my view the lesson here is that, when it comes to an open-back cabinet, there is a great luxury of acceptable variance.  Probably the best sounding of the bunch is the smallest, the old tweed Deluxe, but I don’t think the cabinet dimensions account for much of that.  If anything, it’s the 55 year old nearly floating baffle and pine cab constructions that formulate it’s mojo.  And, of course the circuit itself!  As Fender went on to higher power amps that used bigger speakers, Leo really just made the cabinets as big as was necessary to contain the chassis and speaker while allowing for easy access.  Leo, the old repair man, was always making stuff that was easy to service.

So, my take on an open back cabinet is pretty much this: Make it something that will comfortably accommodate your speaker(s) and other size needs and make it about 9-11 inches deep.  Let the baffle resonate, and use a light resonant wood for the cab itself.  I know, that’s terribly un-scientific, but remember, I come from the Leo Fender school of thought.  Now, let’s think like Jim Marshall.

Marshall may not have invented the closed-back guitar cabinet, but he sure perfected it.  A closed back cabinet has a lot more ability to influence the sound of a Driver than an open back, and I think that here the dimensions become quite important.  Here, I will be very brief.  This wheel has already been invented by Mr. Jim Marshall; we need not re-invent it.  I’ve never heard a closed-back cabinet that sounds better than a Marshall 1960.  Same goes for Marshall’s 1965 4x10 cab and their 1936 2x12 (24x30x12).  Mind you, I’m talking about what folks usually want out of a closed-back cabinet: huge, thumping, tight urgent tone.  The relatively new Marshall 1912 1x12 (18x20x11.5) cab is okay, but I think they skimped on cabinet volume a little.  My personal fav here is the slightly larger Avatar G112 at 24x20.5x11. 

For me, the difference between the really good sounding closed-back cabs and the ones that leave me wanting more usually comes down to this: the bigger box wins.  I always refer to the 1960’s and 1936’s as “big box” cabs, since they are among the largest examples of the form you will find.  Put head to head, a 1960 will blow away an MG 4x12 loaded with the same drivers.  Sure, construction is a little different, but it’s the added size that really matters!

So, back to that "optimum size" calculator.  Don’t use it.  Guitar speaker cabinets are like guitar speakers themselves; what looks good on paper rarely sounds good in real life.  Unlike, say, control room monitors, where you WANT a nice flat and wide response, guitar cabinets, generally speaking, should substantially color the sound.  On paper, transistors whoop butt on tubes, but we all know which usually sounds better in real life.

So, my suggestion on "ideal" size for a closed back cabinet is this: flatter Jim Marshall by copying his best cabinet designs.

Yes, there are a few guitar cabs that use tuned ports/vents to enhance low-end response.  Here, it becomes important to take into account all of the T/S parameters of a given speaker and mate it to a cab that is of the proper dimensions and with the proper port dimensions.  But, this is rare in guitar cabinets, and in real life these cabinets rarely fare as well in real live as on paper.  When you start tuning the vents/ports on a cabinet, you usually are augmenting a narrow band in the lower octaves of human hearing.  Good stuff in the land of bass bins and bass guitar cabs, not usually so good in guitar cabinets (think WOOFY).  Feel free to disagree, post it here if you wish.  Ultimately guitar tone is all about personal preference, and what I’ve laid out here is simply one man’s personal preferences.

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05/24/2015 2:19am

I believe there are designs for a 1 X 12" cab at the AX-84, I haven't heard it, but they come out with some good stuff. Guitarplayer magazine liked the Port City 212 Wave cab. Have you heard either cab and did you like them?



05/08/2020 11:11am

Hi All,

I notice that all the recommended closed cabs for 112 configurations spec out at 2.2± cubic feet internal volume - closed 212s come in at 3.2± cubic feet which may be why they always sound so good. The listed dimensions on 112s seem to be a matter of luggage design because a foot thick box is just easier to carry in one hand, which is totally understandable. Most closed 2x12 cabs are downright awkward, and I have seen several on wheels, but the size really seemed designed for the sound.

I built a prototype cab based on EVH 212 for two Reapers (30w16Ω wired || to 8Ω) that sounded like a great savage deep-throated beast. It was triumphantly LOUD (Yeah!) and HEAVY AS HELL (70+pounds, groan), and prototype-ugly as Calaban. The Great thing about prototypes is you build them, love them for their best qualities for about five seconds, then you want to build another, better version, that has more qualities you like. The bad thing is they'll hang round the shop and sulk at you while you build the next generation. Hate sulking, so I guess that's why the 212 got stripped for screws and cut down to a 112 to try out other things.
SO, Bigger is Better when it comes to cab size for a particular speaker? I can imagine 4cf 112 cabs, and prob. build one too, but there have to be diminishing returns after some point. Bigger sealed cabs equal a "softer" boomy sound because: the more air volume at normal pressure, the more it can easily be compressed and released. The given pressure is the same ambient level inside and out - then the volume has the greatest effect on he strength of the "air" spring - how much give and back pressure the body of air capped by the speaker(s) creates against the back of the same speaker(s). Volume doesn't care how thick or thin the box is, just how much air you get against the back of the speaker cone. There are obviously some physics and math going on here that relate the ideal spring resistance for a particular speaker's performance (Thiel speaker design be damned). It would probably be a relationship between the area of the speaker(s), the degree of cone movement, the frequency range of the speaker (energy), and the volume of air in the cabinet.

I am obviously overthinking this.

What's a good volume to build for a 112 Reaper 30watt closed cab? 2.2±cf? Right.

It's all been done before, just figure out what is important, and why, and go with that.