2x12 closed back cabinet dimensions

Discussion in 'Amps and Cabs' started by dehughes, Apr 6, 2011.

  1. dehughes

    dehughes Supporting Member

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    Hello all,

    I'm looking for a good 2x12 to pair with my Germino Classic 45 and am wondering if there is a recommended size to make the most out of this amp. I know 4x12s are ideal, but they are also very large....as in, my car can't fit a 4x12 inside of it, so the cab would be staying home all the time (pointless, when I need to take the amp with...).

    In general I gravitate towards cabinets with greater depth, but perhaps with a closed back cabinet the depth is irrelevant and the key is internal volume, construction, etc..

    The cabinet I'm eyeing right now is 29.75" W * 11.5" D * 23" H...which seems about right. That has more internal volume per speaker than a 4x12, so I'm wondering if due to the physics of it all I'd be better off with a slightly smaller cabinet.

    It's been a while since I've had a closed back cabinet, so I greatly appreciate your recommendations.
     
  2. dannyr

    dannyr Member

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    I have an Orange 2x12 Closed Back that sounds huge. Dimensions: 30.5" W x 14.5" D x 20" H. Not sure of the weight but it is heavy. Hope that helps.
     
  3. amphog

    amphog Silver Supporting Member

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    That Orange is 2/3 the size of a Marshall 1960b cab. I think that puts it in the oversize world.
     
  4. dehughes

    dehughes Supporting Member

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    Ha! Yeah, that's oversize....

    Cool. Thanks for the input. I figure if I get enough feedback I'll be able to determine a good size for a 2x12 that gets into 4x12 feel but without 4x12 size. :)
     
  5. TD_Madden

    TD_Madden Gold Supporting Member

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    I've got a late model (maybe a couple years old) "Bandmaster VM 212" closed-back cab that's slightly larger....and use WGS' C12N knockoffs. BIG tone in that cab.

    Dimensions (H x W x D): 21.5" x 32" x 12"
     
  6. dehughes

    dehughes Supporting Member

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    Interesting. That's a big cab as well.

    Do any of you guys use batting in the back of your cab?
     
  7. sharpshooter

    sharpshooter Member

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    Part of the answer would be your intended use of the cab. A 4-12 cab has "tunnel vision", in that they "beam" the sound. A 2-12 cab, if in the vertical position will spread the sound out in the horizontal plane.
    But, lots of players don't like the look of their amp head looking like a "T", hanging off on each end, while sitting on the top of a vertical cab.
    If the above is of no consequence, or the cab will be primarily used in the horizontal position, something ~27 x 16 5/8 x 10 5/16 inside dimentions will work well, (some batting), and is a reasonably easy size and weight to manage.
     
  8. dehughes

    dehughes Supporting Member

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    Interesting...I did some math on the volume (space) of a 4x12 per speaker, and found that most 2x12s I've considered actually have MORE internal volume per speaker than a 4x12.

    I like the "beamy" quality of a 4x12. I wonder if the internal volume has anything to do with it? Would a smaller 2x12 be closer to a 4x12 in terms of response/tonality than an oversize 2x12?
     
  9. sharpshooter

    sharpshooter Member

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    Assuming that the speakers are the same, and the internal volume, per speaker is close, the 2-12 will have similar tonality to the 4-12, however, the 2-12 will have a different sound dispersion pattern.
    I use the word "similar"; edge diffraction of the two cabs are different, so the perceived "tone" is somewhat changed.
    The cab with larger internal volume per speaker, will generally exhibit greater bass responce, at the cost of "quickness", (less tight).
    But,, in a mix, with a bass player, a bassy cab could be to much of a good thing.
    Never any easy choices,,,
     
  10. dehughes

    dehughes Supporting Member

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    Good point. I suppose then I should get one with a similar internal volume to a 4x12, as the amp in question is a Germino Classic 45...already an amp with lots of low end.
     
  11. dspellman

    dspellman Senior Member

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    4x12s were never really "designed," they were simply the smallest cabinet Jim Marshall could cram four 12" speakers in. He needed four because the speakers he was using didn't handle power very well (25W or less) and he was building 100W amps. There are no "physics" involved with those cabinets.

    Ideally, you want to build the cabinet to take advantage of the capabilities of the particular speaker that you're using. Each speaker has characteristics that are identified by the manufacturers. You can feed these into formulas and make some decisions about what you want for speaker response and then build the speaker cabinet to complement and enhance those characteristics of the speaker to develop that response. But this sounds more like an "eyeball" project. Generally speaking, for two 12" speakers, you'll want an interior dimension of somewhere between two and three and a half cubic feet. That's a pretty big range. My 2x12s are about 3.5 cu ft in internal volume and are specifically ported for the speakers I use. Measurements are around 29 x 20 x 14 on the exterior. After setbacks and all, the interior is 28" x 19" x 11.5". Working with a slightly larger cabinet like this allows even the largest heads to sit on top when the cabinet is horizontal, and works very well with rack gear (most of which is around 20" wide) when it's put up on end.
     
  12. Jef Bardsley

    Jef Bardsley Member

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    A Marshall 1922 is 25.6" x 20.5" x 10".
    A Marshall 1936 is 29.5" x 23.6" x 12".

    The average outside dimensions of 15 2x12 commercial cabs (including the Marshalls, a few low enders and a few "boutique" makers) is 26.67" x 20.54" x 12.87".

    The average internal volume of these cabs is 6374.13 cubic inches. The largest is the Yellow Cab, at 9315 cubes, and the smallest is the PC Wave at 4536.

    For reference, a Marshall straight 4x12 is about 1,1129 cubic inches.

    You are right that the internal volume is the most important factor, but because of the large panels, a 4x12 has more losses than a 12x12, so there's no direct comparison. That is, a 2x12 should be a bit larger than half a 4x12.

    Hope that helps,
    Jef
     
  13. dspellman

    dspellman Senior Member

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    I usually try to design my gear for maximum range and efficiency. You can always EQ it out if you don't want it, but you can't put it back in if it was never there to begin with.

    A JTM-45 clone like your Geronimo puts out 30-40 watts and, like most Marshall tone circuits, has a noticeable dip in the 800Hz range which gives you a bump around 150Hz, which you hear as "lots of low end." What you'll find is that it sounds a bit bottom-heavy when you're sitting around playing within sitting distance of it, but when the volume goes up, it actually runs out of power to support the bottom end and you start losing it. Not a bad thing -- just a characteristic of the amp. It takes a lot of power to produce the bass side of things (thus you have bass players with 2000W amps).

    If you add bass capabilities and efficiency to your cabinet, you have the luxury of dialing it back a bit for practice and sitting distance noodling, but can crank your amp up a tiny bit more without losing your bottom when you want it.
     
  14. dehughes

    dehughes Supporting Member

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    That is one of the single most helpful answers to any question I've ever put up on any internet form. My goodness....THANK YOU!

    Are you a cabinet builder, Jef? What compelled you to compile that information? Any recommendations for cabinets I should look into?
     
  15. dehughes

    dehughes Supporting Member

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    Wow, two in a row! You guys are the greatest.

    If I understand you then, I should not look to thin out the amp via the cabinet, but just get a cabinet that let's the amp be what it is. Based upon your post and Jef's post, it seems a 2x12 closed back cabinet with about 3,100 cubic inches per speaker would do fine, assuming it's a quality built cabinet, etc. etc...

    What cabinet would you recommend for my JTM-45? I've been eying the THD 2x12 and the Mojave 2x12, but my inclination is to either 1) pick up a used Germino 2x12 or, 2) have Mather build one of his 2x12s for me.

    Oh, and I intend on using standard, re-issue 25w G12M Greenbacks.
     
  16. Jef Bardsley

    Jef Bardsley Member

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    Actually, yes, I design custom guitar cabinets for clients that want something their wife will allow in the living room or studio owners that want a showpiece. That list is titled, "Competitor's Cabs". I'd been meaning to work out the averages, and since you asked..... ;)

    I'd take a look at TRM cabs, as I've heard good things about them.
    http://www.trmguitarcabs.com/

    Myself, I'd go with a pine cab finished with tung oil for a Greenback 2x12. It would add quite a bit of musicality, and I'm guessing your not playing Death Metal (if you are, then I'd lean to the Tolexed plywood to keep the sound cleaner).

    Incidentally, Greenbacks have a bit of a bump on the bottom end themselves, so the bigger the better to move it dowwards, away from the Marshall bump dspellman mentioned.
     
  17. inca_roads

    inca_roads Member

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    Don't overlook a Marshall 1966-style (vertical/diagonal) 2x12. Reinhardt makes a similar one as well.
     
  18. dehughes

    dehughes Supporting Member

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    Thanks Jef! Super helpful...

    Regarding the pine cab with tung oil....I'm looking for something to be able to touch upon AC/DC, Wilco, indie stuff, and jazz. Maybe that's too much...but the JTM-45 is a super versatile platform, and I'd like my cabinet to be equally versatile. Would you still recommend pine for such an endeavor?

    Also, do you have a website?

    Inca, I'll have to look into that one. I've never taken newer model Marshall 2x12s seriously...but I'll take a look at that 1966 and the Reinhardt equivalent.
     
  19. Jef Bardsley

    Jef Bardsley Member

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    Yes, I'd still go with pine. I play through a dimed Marshall myself, and really like the sound. The shredder Death Metal guys have special needs - when you play that fast you don't want resonances cluttering up the (tiny) spaces between the notes. That why pianos have sustain pedals and some banjo players use dampers on their strings.

    No website yet, but I'm working on it. ;)
     
  20. dehughes

    dehughes Supporting Member

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    Very cool. Thanks Jef! Would you add my e-mail to the list of people you'll notify when your website goes live?
     

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