Wayne's 12Pi sub

[scameron78]

anyone build one? i've seen all the information on it and he sent me the plans yesterday. i am considering, but the box is huge. seems moving them wouldn't be too bad with the grab handle and wheels. the band i play will be doing some outdoor shows this summer, but i think i could use these inside also. anyone hear this cabinet in person? however not much bigger then the dual 18 manifold i was trying to design. i am an engineer at a wood working company so building them wouldn't be an issue. i have access to cnc machining.

[Top Shelf]

Is this the same 12 Pi that is similar to the Lab 12 pro box? If you haven't already checked out prosound forums you should they love them over there.

[scameron78]

yeah it is similar. i have plans for the labsub also, but actually it is a little more intense to build due to some compound miter cuts. thought i would look at other forums on opinions. seems on the prosound forums everyone is biased towards the labhorn as with Bill Fitzmaurice's designs on his forum. i have been wanting to build some push-pull dual 18 cabinets, but i forgot about Wayne's 12Pi and how they used the push-pull concept also. the box is big, but would only be deeper compared to a dual 18 cabinet.

[Top Shelf]

Setting aside the non-linearity cancellation of push pull in the 12 Pi , it'd be nice (from a prosound perspective, high voltage / low frequency) to have a version with both lab12 magnets in the throat
chamber for even voice coil cooling. Though it might detract from the already small 21 L? sealed
boxes in these enclosures. What do you think?

[weltersys]

Originally Posted by scameron78

yeah it is similar. i have plans for the labsub also, but actually it is a little more intense to build due to some compound miter cuts. thought i would look at other forums on opinions. seems on the prosound forums everyone is biased towards the labhorn as with Bill Fitzmaurice's designs on his forum. i have been wanting to build some push-pull dual 18 cabinets, but i forgot about Wayne's 12Pi and how they used the push-pull concept also. the box is big, but would only be deeper compared to a dual 18 cabinet.

The 12 Pi is almost double the volume of a typical dual 18" box. That 45" depth may not be a problem outside, but indoors may be. I have not used 45” deep cabinets since the late 1980’s, they just didn’t fit in too many venues.

If you compare the graphs of the 12 Pi to a JBL SRX 728 ( 98 dB one watt one meter at around 80 Hz) you see the 728 actually puts out more level at 50 Hz.

You could put almost two of the 728 in the same truck space as the 12 Pi, and two 728 would give another 6 dB over one.

My single 18" Keystone cabinet, 45” x 26.5” x 22.5”, about exactly half the volume of the 12 Pi, is very close to the same sensitivity and frequency response of the JBL SRX 728, the 728 has a bit more output below 37 Hz, the Keystone a bit more above 80 Hz.

Keystone Sub Using 18,15,&12 Inch Speakers

Two Lab 12 in the Keystone enclosure are even more sensitive than the BC18SW115-4, but can't take as much power without thermal compression and running out of excursion, the BC18SW115-4 will put out more SPL given more power.

Two dual Lab 12 in ported cabinets half the size of the Keystone sub comes out to the about the same size and level as the single 18” Keystone, but uses twice the amplification.
Two dual Lab 12 have more LF output than the JBL SRX 728 and take up less space.
You could fit four of them in the space of one 12 Pi, and not get a hernia doing it.

As far as the reduction in distortion due to push pull, a brief look at the 12 Pi distortion compared to the Lab 12s in ported or TH cabinets shows that the 12 Pi has perhaps a bit more distortion than the normally mounted ported 12”, and a bit less than the normally mounted 12” in the TH.

As long as the Lab 12 is run below Xmax, distortion is not much of an issue no matter the configuration. The BC18SW115-4 will get a lot louder with less distortion than a pair of Lab 12s though.

Art Welter

[scameron78]

i heard a pair of EV MTL-4s the other night being used for a live band and loved them. More sound then my 4 peavey 118-HCs (double number drives acourse). how would the keystone sound running a Peavey lowrider 18? or maybe the 1801-8 in the 118-HCs.

[Don Snyder]

The LabHorn was designed to the requirements of the ProSoundLab members. In a stack of 6, it's great. In singles or duals it is useless. During it's first
year, Wayne spent his time bitching about how it didn't meet HIS requirements.

Don't build this design, neither the LabHorn or the 12Pi, in singles ... you won't be happy!!!

[weltersys]

Originally Posted by scameron78

i heard a pair of EV MTL-4s the other night being used for a live band and loved them. More sound then my 4 peavey 118-HCs (double number drives acourse). how would the keystone sound running a Peavey lowrider 18? or maybe the 1801-8 in the 118-HCs.

Doubling drivers and power results in a six dB level increase, no mystery why eight 18s would sound louder than four.
EV MTL-4s get loud and punchy, but roll off steeply below 45 Hz, about 10 Hz higher than the Keystone.
If that low corner works for you, and you can afford all the cones, the MTL-4 design would be hard to beat, output vs. truck space.
However, LF extension always comes with either an increase in size or a loss in level.

I have not tried the Low rider 18 in the Keystone TH. From Hornresp simulations it looks OK, but is not close to the power handling and excursion capability of the BC18SW115. I'd expect it may "mush out" if driven hard in a TH.

Art

[scameron78]

this was the design i was playing with. similar to djk's designs.

preliminary dual 18 manifold

[weltersys]

Originally Posted by scameron78

this was the design i was playing with. similar to djk's designs.

preliminary dual 18 manifold

That design should work OK.
If I were building it, I'd use truck box integer dimensions.