Planning on making a 212 Thiele, and have some questions

I've read this thead and this thread from beginning to end.

Can I technically double the width of a TL806 and make a 212 Thiele cabinet? Loaded with two EVM12L's of course. I notices that the 412 cabinet has four times the volume of the 112 so I think this would work, but I want to make sure.

I have a Mark IV combo by the way.

I would have to wire it "weird" I guess. Since 12Ls are 8 ohms, I think there are a few options as to how I could run them. Please tell me if I'm correct. I want to run the combo speaker (8 OHMS) with it.

I could run them both separately and plug both speakers into the 4OHM jacks. The combo speaker stays in the 8 OHM jack.

I could wire them in parallel and plug the cab into a 4 OHM jack. The combo speaker stays in the 8 OHM jack.

I could wire the speakers in series while in parallel with a dummy 16 ohm load, and plug the cab and combo speaker into the 4OHM jacks.

I can probably also figure out a switch to be able to change between the second and third option.


I plan on making this with a metal grill and out of baltic birch or some other super durable plywood. I don't want to have to haul this in a case, so instead of tolex I'll use that stuff that Vader cabinets use, the stuff used on truck beds.


Thanks for any help guys!

making a double thiele just takes a little forethough and planning. totally doable. as far as a dummy load, don't bother. wire the cab as a 4 ohm or 16 ohm. the only way to get 8 ohms with two drivers is with 4 or 16 ohm drivers. the dummy load will not work. trust me bass players would love to be able to switch a cab's impedance (in our case 4 to 8 ohms) but as of right now that is either impossible or too much trouble to be practical.

anyway, with a double theile i would disconnect your mark's internal preaker. you will probably like the sound better.

Boogafunk said:

making a double thiele just takes a little forethough and planning. totally doable. as far as a dummy load, don't bother. wire the cab as a 4 ohm or 16 ohm. the only way to get 8 ohms with two drivers is with 4 or 16 ohm drivers. the dummy load will not work. trust me bass players would love to be able to switch a cab's impedance (in our case 4 to 8 ohms) but as of right now that is either impossible or too much trouble to be practical.

anyway, with a double theile i would disconnect your mark's internal preaker. you will probably like the sound better.

Click to expand...

Thanks for the info!

I want to still be able to use the combo speaker as a monitor during shows. Point the sweet sound of the Thiele at the audience, and be able to hear myself.

I've also seen a few 4 ohm EVM 12Ls after posting my original post, so if I'm able to find two of those I can wire them in series for a total of 8 OHMs of resistance.

One of our fellow posters has one that was built for him.





Totally one-off, and and a cannon by all reports.

Ohhhh Poe... come show off your toy!

good looking cab. personally i would turn it with the ports on the bottom, or better yet turn it on its side. the "wall paper" is quite cool, however, i would line the inside with some foam or some other acoustic damping material. (that's just splitting hairs though) very nice.