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dehughes
04-06-2011, 11:25 AM
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.

dannyr
04-06-2011, 12:10 PM
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.

amphog
04-06-2011, 12:22 PM
That Orange is 2/3 the size of a Marshall 1960b cab. I think that puts it in the oversize world.

dehughes
04-06-2011, 12:42 PM
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. :)

TD_Madden
04-06-2011, 12:43 PM
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"

dehughes
04-06-2011, 01:22 PM
Interesting. That's a big cab as well.

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

sharpshooter
04-06-2011, 06:51 PM
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.

dehughes
04-06-2011, 07:16 PM
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.


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?

sharpshooter
04-06-2011, 08:13 PM
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,,,

dehughes
04-06-2011, 11:03 PM
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,,,

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.

dspellman
04-07-2011, 12:25 AM
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.

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.


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.

Jef Bardsley
04-07-2011, 07:59 AM
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

dspellman
04-07-2011, 09:04 AM
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.

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.

dehughes
04-07-2011, 09:50 AM
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

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?

dehughes
04-07-2011, 09:54 AM
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.

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.

Jef Bardsley
04-07-2011, 12:02 PM
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?
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.

inca_roads
04-07-2011, 12:45 PM
Don't overlook a Marshall 1966-style (vertical/diagonal) 2x12. Reinhardt makes a similar one as well.

dehughes
04-07-2011, 09:35 PM
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.

Jef Bardsley
04-08-2011, 03:59 PM
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. ;)

dehughes
04-08-2011, 10:09 PM
Very cool. Thanks Jef! Would you add my e-mail to the list of people you'll notify when your website goes live?

papersoul
04-10-2011, 08:28 PM
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.

If it is important to build a cab to accomodate the speaker, how come some amp cab builders offer many different speaker choices per cab? Just curious.

schwa
04-10-2011, 08:41 PM
I don't know how wide the Germino amp is, but my favorite 2x12 is the Mojo 2x12 slant in the Marshall syle. It's 26" wide, a little bit bigger than the Marshall 1966.

Fits fine in the trunk of my car.

Jef Bardsley
04-11-2011, 03:19 AM
If it is important to build a cab to accomodate the speaker, how come some amp cab builders offer many different speaker choices per cab? Just curious.
Because cutting the size of a ported cabinet (or the size of the port) by one half only changes the resonance by a factor of 1.42, and in fact, many would prefer the response of the smaller box despite the poor phase response. In other words, if your target is a Butterworth roll-off @ 50 Hz, even such an extreme mismatch in the cabinet size will merely raise the Fs to 71 Hz, a rather moot difference for an instrument whose lowest note is 81 Hz.

The changes in a sealed enclosure (closed back, no port) are even less. More to the point, the average Vas (size of box for equivalent compliance) for guitar speakers is about 2600 cu. in., so you can see from the sizes I posted earlier most guitar cabs qualify as "infinite baffles", thus changing the size will not alter the speaker's response at all and any tonal differences will be due to changes in panel resonances.

The specs for guitar speakers fall in a very narrow range compared to what's available for hifi speakers, so warnings about how critical cabinet size is in a field where there is no performance standard (even our guitars don't have the same bass output, never mind the EQ difference between Fender and Marshall amps) tend to be overstated. I'm afraid I've been guilty of that, myself, in the past. :cool:

Now, if we're talking horns or transmission lines, then things do become a bit more critical, but for the most part, no one uses those for guitars due to excessive size.

dehughes
04-11-2011, 10:13 PM
Great post again, Jef!

So, are you saying that one needs not as large a 2x12 box as is assumed for the sake of speaker response, for up to a certain point the changes in tone/vibe are a result of the cabinet's resonance instead of its size?

That is, a smaller 2x12 can be just dandy for doing the "closed back thing", and differences between a good small cab and a good large cab are a result of the different sizes of the baffle/top/back/sides resonating differently, not a result of the speakers being in a larger or smaller enclosure?

Jef Bardsley
04-12-2011, 07:05 AM
So, are you saying that one needs not as large a 2x12 box as is assumed for the sake of speaker response, for up to a certain point the changes in tone/vibe are a result of the cabinet's resonance instead of its size?

I'd say beyond a certain point, the response of the speaker will be the same, though the smallest sizes on the market will constrict the bass a bit. Larger cabs will pretty much always sound larger, as our ears are rather sensitive to size cues.

That is, a smaller 2x12 can be just dandy for doing the "closed back thing", and differences between a good small cab and a good large cab are a result of the different sizes of the baffle/top/back/sides resonating differently, not a result of the speakers being in a larger or smaller enclosure?

In my last post I'm not saying they all sound the same, but rather that when you use a different speaker than the designer did, the odds are it will still "work".

There's also a seldom mentioned (on guitar pages) issue with reflected sound coming through the speaker cone which will audibly alter the tone, and as the cab gets smaller and the back gets closer, this becomes more of an issue.

But yes, most of the differences in tone between cabs are the result of other things than the actual bass response of speaker.

Note that "room EQ" (the reinforcement of bass frequencies due to reflections) is a bigger factor than the cab, unless you're in an auditorium or outdoors. For this reason, to fairly compare two cabs they need to be placed in exactly the same spot.

And I just posted this link in another thread:
http://www.ethanwiner.com/believe.html
which stresses that to make fair comparisons, our ears need to be in the same position, as well.

And for those that are wondering, yes, I do have calibrated measurement microphones and several software packages for taking measurements. I'm not offering a Readers' Digest Condensed version of someone else's theory here, these are things I have learned from 40 years of hands on experience.

The collected wisdom of all the hifi guys is not much use to us guitar player types. For instance, the highly regarded Thiele/Small alignments are only useful for "small signal" applications. Unless your software can compensate for the thermal effects of pushing 100 watts through the voice coil you're not going to get accurate results in a real life situation. More importantly, at the levels we play at, the walls of the cabinet become translucent, passing all frequencies to some degree, and again, the typical assumption of an inert material made by most programs will oversize the results. While the hifi guys have something they call "aperiodic vents" (found in the old Dynaco speakers), guitar cabs can be considered truly aperiodic enclosures.

Actually, it's this near transparency that makes pine sound so good. As someone else mentioned, you won't get the same tight thump you would from plywood, but you can get most of the bass of a closed cab with some of the openness of a combo.

dehughes
04-12-2011, 03:31 PM
Huh. Very cool. Thanks, Jef.

sepulchre
05-14-2013, 10:26 PM
This should be a sticky. Excellent info here. Thanks, if somewhat late.