Experience With 4/12 Cab Loaded With 2/12s ?
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- 212 412 cab speaker cabinet
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not sure why people are always asking about this (there's quite a few threads here), but, IMO, the cab isn't designed for it.
That said, What you should do, is cut 2 pieces of plywood 12"x12" (square, or circle). Put a speaker over the wood & drill 4 holes, using the speaker holes as guides. Then put some sort of rubber sealer (gasket) around the speaker hole & screw the panel on like a speaker.
You could experiment w/ ports, by using a hole saw to add a port, or 2 in the new pieces of wood.
Another thing you could try is adding a passive radiator instead of one of the speakers, for more bass.
That said, What you should do, is cut 2 pieces of plywood 12"x12" (square, or circle). Put a speaker over the wood & drill 4 holes, using the speaker holes as guides. Then put some sort of rubber sealer (gasket) around the speaker hole & screw the panel on like a speaker.
You could experiment w/ ports, by using a hole saw to add a port, or 2 in the new pieces of wood.
Another thing you could try is adding a passive radiator instead of one of the speakers, for more bass.
My apologies @Dogs of Doom for not finding the threads regarding said .. Thanks for the tips too !
I'm wondering if any of you awesome MF'rs have actually messed around with this ……
More specifically …… I picked up an AVT412AX yesterday loaded with the stock G12-412s and it sounds just awful IMHO …… The small (26-1/2") form factor is perfect though …… adjustable porting methods to achieve the passive radiator have already starting formulating in my hack mind…… I'm just fine with more of that low/mid responce thing ……
I'm wondering if any of you awesome MF'rs have actually messed around with this ……
More specifically …… I picked up an AVT412AX yesterday loaded with the stock G12-412s and it sounds just awful IMHO …… The small (26-1/2") form factor is perfect though …… adjustable porting methods to achieve the passive radiator have already starting formulating in my hack mind…… I'm just fine with more of that low/mid responce thing ……
no biggie, I just, for the most part don't understand the logic, so thanks for explaining it to me.
I can see that, w/ an MDF/undersized cab, you might want to do this. It's just when I see people w/ 1960 cab's asking this, I wonder why...
We've had people port their MDF/MG cab's by hacking a few inches off the rear panel & they said that they liked the result. They also added insulation sometimes for desired effect.
My experience w/ MDF 4x12 cab's is that they get woofie, when driven. This is probably why they designed them undersized, because of the structural properties of the MDF, vs a laminated wood.
Turning it into a 2x12 might be a good thing, as long as you deal w/ the other 2 holes properly & if you vent it, try & tune it well.
Funny, I have an AVT 112 cab & it actually sounds great w/ a greenback, better than my 1912 cab's. The AVT 112 is an oversized cab, which I think sounds a bit less boxy, than the smaller 1912.
If you've got a good deal, I'd still say, try & make whatever mod's reversible, so you can put it back stock & flip it, if you want, but, you should be able to fill the holes & if you port it, port the pieces that you fill the holes w/. You can always add some insulation & remove it, or leave it.
I can see that, w/ an MDF/undersized cab, you might want to do this. It's just when I see people w/ 1960 cab's asking this, I wonder why...
We've had people port their MDF/MG cab's by hacking a few inches off the rear panel & they said that they liked the result. They also added insulation sometimes for desired effect.
My experience w/ MDF 4x12 cab's is that they get woofie, when driven. This is probably why they designed them undersized, because of the structural properties of the MDF, vs a laminated wood.
Turning it into a 2x12 might be a good thing, as long as you deal w/ the other 2 holes properly & if you vent it, try & tune it well.
Funny, I have an AVT 112 cab & it actually sounds great w/ a greenback, better than my 1912 cab's. The AVT 112 is an oversized cab, which I think sounds a bit less boxy, than the smaller 1912.
If you've got a good deal, I'd still say, try & make whatever mod's reversible, so you can put it back stock & flip it, if you want, but, you should be able to fill the holes & if you port it, port the pieces that you fill the holes w/. You can always add some insulation & remove it, or leave it.
JohnH
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I did this with my 8412 (valvestate ancestor of your AVT cab), keeping top two drivers and blanking off lower ones with 9mm ply, painted black. My reason was because I needed a 16ohm cab. It worked well and made a great extension or main cab as a 2x12.
I sold ths cab, but had I kept it my plan was to get a couple of nicer speakers to replace the top two.
I sold ths cab, but had I kept it my plan was to get a couple of nicer speakers to replace the top two.
I've got a few good speakers that I can experiment with .. I would like to make this a 16ohm cab as well .. A couple of V30 8ohms don't have a home so I'll give those a shot in series 1st up .. 100bones is all I have into it so I'm pretty easy on the poke and prod front .. It would be great to get a less forgiving (tighter) response as opposed to sag .. Is the shape of the porting a major consideration .. It would be nice to just have an adjustable slot (so to speak) by gapping covers over the unloaded holes...
I'd probably try diagonal w/ the speakers...
Ironically, Marshall seems to just put a 3" hole in the baffle, in their smaller cab's.
The way you tune, w/ a port tube, is diameter vs length. If you just put a hole, it'll just push out air. If you have a tube, then you start getting into precise tuning. You have to be careful, not to get too much length vs round. You can get some breathing, but mostly w/ lower bass frequencies. Probably an easy way is to get a doorknob hole saw (2") & put a hole in either 1 or both of the new speaker filler baffles.
Having front port, vs rear port, will give you a tighter bass. Maybe try it w/o any ports 1st. If you don't like it, then start porting it. If you port it, & it sounds mushy, pad the interior w/ insulation. You might even try no port & insulation 1st.
JohnH
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With ports, I doubt youd need them in what would be a well-oversized 2x12. But if you want to try them, its a good idea to load up some software such as WinISD for checking the tuning frequency. Too high a port resonance causes a bass or low mid boom. On my 1x12, I tuned the ports to just below guitar frequency, so no boom but the upper tail of the resonance lifted the low bass. (it works well, but when I posted that on an audio forum to check it out, I was told I has totally full of BS and should be ashamed of myself)
Ports work together as a group, in relation to cab volume. Lower resonant frequency comes from longer ports or smaller diameter ports, or fewer ports. When Marshall put a 3" hole in a baffle, it is effectively a port tuned to a frequency based on the port length being the baffle thickness, whether or not that is what they intended.
Ports work together as a group, in relation to cab volume. Lower resonant frequency comes from longer ports or smaller diameter ports, or fewer ports. When Marshall put a 3" hole in a baffle, it is effectively a port tuned to a frequency based on the port length being the baffle thickness, whether or not that is what they intended.
Zues Sota
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Hi John
The best solution is to load two passive radiator/dummy speakers in the bottom. They will act as reflex speakers. Sound waves will actually vibrate the the cones on the unhooked dummy speakers and produce some sound. It use to be a home audio marketing trick back in the 70s and 80s. By Polk Audio and others. When tall cabinets loaded with multiple speakers were popular. Cheap speaker cabs would often have one or two passive reflex speakers. And they would be counted as speakers in the advertisement. Two V30s and two dummies on the bottom sound great! Choose your passive dummy speakers with a cone tap and stroke. Lightly tap the cone and then lightly stroke or drag you finger tip across the cones surface. This will give you an idea of the sound frequency the dummy will generate. Got old speakers laying around. Compare them to your V30s. The passive speakers will not generate enough output to make any big noticeable difference. Because of their loction. Unless you are close and in their direct path. But you can definitely mic them in addition to your main speakers. You may find a mic placement some where on the cone that generates somthing you like. Similar to using a room ambient mic. Or miking the back of speaker.
Zues
BowerR64
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Just leave the speakers in and unhook em. They wont move as easy as a radiator but they still will put out low bass. You can then run just the top 2 or criss cross em and see how it sounds.
Ive done all of these above. I also made 12" rings and put 2X10" in a 4X12 those 10s sounded so HUGE in the 4X12
I think open or ported guitar cabinets sound better at low to moderate sound levels. Once you start getting them loud or gig levels most guitar speakers cant handle it and they crap out or what people call "break up" they sound like shit.
The sealed cabinet holds the cone together better at high levels and they sound tight and controlled.
IMO 2X12 in the volume of a typical 4X12 gives a larger frequency because it allows the lower frequencies to breath. The idea of the 4X12 is to extend the mid frequencies and sort of choke off the lower frequencies that the bass player is suppose to cover.
Ive done all of these above. I also made 12" rings and put 2X10" in a 4X12 those 10s sounded so HUGE in the 4X12
I think open or ported guitar cabinets sound better at low to moderate sound levels. Once you start getting them loud or gig levels most guitar speakers cant handle it and they crap out or what people call "break up" they sound like shit.
The sealed cabinet holds the cone together better at high levels and they sound tight and controlled.
IMO 2X12 in the volume of a typical 4X12 gives a larger frequency because it allows the lower frequencies to breath. The idea of the 4X12 is to extend the mid frequencies and sort of choke off the lower frequencies that the bass player is suppose to cover.
KraftyBob
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Do a search on Detuned cabs.
Update !! I'm loving the responce and tone of Attempt #1
It couldn't have been easier ( so far )
Top 2 'G12-412AVT' removed
An Eminence Patriot Red, White & Blues 8ohm and
A V30 8ohm
Wired in series
Bottom 2 Stock Speakers in place but disco'd as Passive Radiators
Sounds Great
Of course me being me , I'll change it again after learning a bit of tech bo-garble ……
Thanks again for the tips guys !!!
It couldn't have been easier ( so far )
Top 2 'G12-412AVT' removed
An Eminence Patriot Red, White & Blues 8ohm and
A V30 8ohm
Wired in series
Bottom 2 Stock Speakers in place but disco'd as Passive Radiators
Sounds Great
Of course me being me , I'll change it again after learning a bit of tech bo-garble ……
Thanks again for the tips guys !!!
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I have a pair of Vintage 30's as well, just sitting in boxes in a closet, looking for a home.
I'm on the look-out for a used 2x12 (empty).....maybe a 1936, but maybe a slanted one. Whatever I come across.
Wouldn't passive radiator speakers need a very-well sealed enclosure to be effective. I'd think something as small as an unused daisy-chain jack hole would cause the passive speaker cone not to move. (.....?......)
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How about a Seismic or Avatar cab ?
Agreed …… I lucked out on the 412AVT cab …… it's tight and the plastic cone thingy has one sealed phone jack with just the right depth to keep a standard plug protected from the drummer
I just bought a Avatar 2x12 like a month ago. They are good but NEW and thus, expensive. I've seen a lot of those seismic cabs and I get that they're inexpensive but I don't have any experience with them, plus many are front loaded, and I like rear-loaded speakers better.
Zues Sota
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I run my Mesa Boggie MKV through a modified half back 4x12 1960 anniversary. Loaded with G12 vintage 70w in the top. And Governor Red Coats in the enclosed bottom. That configuration truly sounds amazing in small venues. Incredibly versatile for any style. And here is a true story for you folks. Years ago one of my good friends, Darrel Newton. (Some here may have even known him or the name. ) Experimenting, he took out the bottom two green backs to see if it would open up and cut through in live gigs. And he like the results so much. I think he pretty much adopted that configuration. His band mate Tony liked the sound so much he did the same with his cabinet. And later sold the other ones he took out for some quick cash. Which started somewhat of a trend with some of the locals. To my good friend Darrel, you will always be in heart and on my mind. Love you brother! RIP
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junk notes
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