The dual lab 12 design looks really nice especially if extended LF output in a small box matters more than absolute output at a little higher frequency. I am anticipating a sub build coming up for the church youth system (the 21" RCF cabs I built previously were so good that they got taken from the youth system I built them for and used in our main sanctuary system in place of 3 EAW dual 15's). So I am strongly considering a pair of the dual lab 12's here vs a pair of single 18" cabs. Because of cost I would opt for the tbx100 rather than the sw115 (one tbx100 costs about the same as 2 lab 12's). So from your testing of the dual lab 12 vs sw115 you say the sw115 will give 3db more output with twice the power. B&C has a recommended enclosure for the sw115 with fb of 35 hz and excursion limited output of 124.9 db and their recommended enclosure for tbx 100 gives fb of 34 hz and excursion limited output of 120.3 db. Given that, do you think it would be safe to say the tbx100 in said enclosure would be pretty similar to your dual lab12 design. Granted the box for the tbx 100 is a fair bit larger. Does the single 18" have any advantage I am missing or would the dual lab 12 be a better choice since the box is smaller and output is very similar? Power will likely be an MA2400 so that would be one dual lab 12 per channel or both 18's on the bridged amp so the dual lab 12 would likely see slightly less power but not significantly so.Thanks for any thoughts,Loren JonesThe dual Lab 12 has almost identical low frequency output in a smaller box with the same Fb as the BC18SW115-4.The BC18SW115-4, given twice the power, will get about 3 dB louder than the Lab 2x12.But it takes a bigger box to do it.The exterior dimensions of the box I used to test the BC18SW115-4 are 36 x 24 x 17 inch, 8.5 cubic feet compared to 7.76 for the 2x12. In all but the 38 Fb test, the magnet was outside the box, effectively adding about .56 of a cubic foot. That said, bigger is better (until Xmax is exceeded before Pmax) but the boxes are very close in volume.The BC18SW115-4 with the 37 Hz tuning almost exactly overlays the Lab 12, were it not for the lower upper filter on the Lab 12 , they would look more identical.Art Welter
Loren,So from your testing of the dual lab 12 vs sw115 you say the sw115 will give 3db more output with twice the power. B&C has a recommended enclosure for the sw115 with fb of 35 hz and excursion limited output of 124.9 db and their recommended enclosure for tbx 100 gives fb of 34 hz and excursion limited output of 120.3 db. Given that, do you think it would be safe to say the tbx100 in said enclosure would be pretty similar to your dual lab12 design. Granted the box for the tbx 100 is a fair bit larger. Does the single 18" have any advantage I am missing or would the dual lab 12 be a better choice since the box is smaller and output is very similar?
Just looked here and found your questions unanswered for two months..
Given enough power, the B&C18SW115 definitely will outperform a pair of Lab 12" but will require a much larger BR cabinet.
The ceramic magnet B&C18TBW100 is very nearly the equal to the B&C18SW115 but is much lower cost now that Neo pricing has skyrocketed.
The B&C TBX100 series at 11mm has slightly less Xmax than the Lab 12, there is no replacement for displacement.
That said, a pair of B&C12TBX100 can outperform the Lab 12 in all but the VLF range in a smaller cabinet according to simulations.
The other thought i had was wiring the current version in series and then connecting the 2nd cab to give you a total of 3 ohms.
The only problem i see is no amps are rated at 3ohms, but to be safe i would say only use a 2ohm rated amp.
I think the 12C is more oriented for car audio, where a single speaker with low impedance is more useful.
The 500 watt Lab 12C is only 3.11 ohms (compared to 400 watt 4.29 ohms for the Lab 12) , so at the impedance minima a pair in series will be about 6.2 ohms.
If you want a lot of power (between 1600-2000) series the pair and run the amp bridged mono.
At 1.55 ohms for a pair in parallel, even some 2 ohm rated amps will cough with that load.
The Lab motor is not very effective at getting rid of heat, my guess is very little (if anything) would be gained using the extra power the 12C can take, I'd just use Lab12 and parallel a pair of them on any amp that puts out more at 2 ohms than 4.
My experience is that depending on the amp, a rating between 1000 to 2000 watts is about right for a pair of Lab 12 in the ported cabinet.Thanks for the insight Art. My reason for wanting to wire a pair of Lab 12C in series was so that I could eventually run 2 per channel on a XTi6000 (or a potential IT4000 that I may have a line on), you think it would be smarter to wire a pair of Lab 12 in parallel and then run 1 per channel on an amp that puts out a bit less power then?
My experience is that depending on the amp, a rating between 1000 to 2000 watts is about right for a pair of Lab 12 in the ported cabinet.
My experience has been that some switching power supply amps need to be rated at double or more the power of "heavy metal" amps to be equivalent in low frequency output.
I have no A/B experience with the XTi6000 compared to any amps I know, so can't be of much specific help other than I'd want to see a rating of no less than 1000 watts per Lab 12 cone on a switching PSU amp.
The grill angle piece is just a 45" angle mitered short enough to not interfere with the grill.Project got delayed for the holidays, just ordered some parts today. I've been studying all the attachments in this thread and think I have a good grasp of the build process. Art, you wouldn't happen to have any pictures of the Grill Angle Piece meeting with the baffle. Looks like there is going to be some carefully cut angles involved to get those pieces to mate properly.
The grill angle piece is glued to the baffle, it directs the port output around the grill.Thanks Art. So from the look of the picture, the Grill Angle Piece doesn't come into contact with the Baffle, it merely provides at attachment point for the Grill Piece?
Looking forward to finally making some dust.
Reduction of port area will slightly lower the tuning and increase velocity.I thought I had the perfect placement for my handles sorted out, until I put the baffle in place and realized that one handle is going to protrude into the area of the upper port. Is this going to be a problem? Would it be worth backing the handles with 1/2" ply instead of 3/4" to minimize it's effects on port area?