$325 Lab 12 based PA tapped horn ~ 35Hz extension

lol no idea. I had drawn out the circle with my protractor and just had him follow it. Maybe he thought I was rushing him and wanted it done fast. Either way I am using a jig to make sure its fixed and done right.

As long as the circle lines up with the inside edge of the gasket, and does not protrude into the area where the surround is, do the edges of the cut-out need to be chamfered at all on a 45 degree etc?
 
lol no idea. I had drawn out the circle with my protractor and just had him follow it. Maybe he thought I was rushing him and wanted it done fast. Either way I am using a jig to make sure its fixed and done right.

As long as the circle lines up with the inside edge of the gasket, and does not protrude into the area where the surround is, do the edges of the cut-out need to be chamfered at all on a 45 degree etc?

IMO the edges do not need to be chamfered. That actually increases the risk of an air-leak.
 
If both are being powered by the same amp, and same processed signal, shouldn't both subwoofers be identical?

If so, which I think they should, then you should make the same modification to both....
And a 3/4" "plate" with a new cutout should deal better than just a small ring.

Just make sure when you place the plate in the horn, that you keep the center at the correct L12 distance...
 
I will be doing the mod to both units to be identical.

As for the ring, it will be wider than the sub, almost touching the edges of the opening so it will be beefy. Pl"d to the original opening and using the t nuts in the original location should yield a strong hold. I will be adding some dap around the edges and in the screw hole area regardless. In my bfm builds I did the same as I had small leaks regardless of how tight the woofer gasket was.
 
Just helped my prosound buddy set up his new smaller rig with four of these and his mini line arrays, under a tent...they really work. Impressive. A bunch easier to handle than his LAB12 horns, and maybe just as good overall, SPL aside of course. Guess I'll have to do one for my shop. Or two.
 
Thank you for your time in making and posting this design. 5/8 sent a post about what he heard and saw with the 4 PAL12's I have built. I have been watching this site for a while and was ready to build a tapped horn but for the LAB 15 by Dag. I have been waiting on money from an install to purchase the 15" speakers when your design showed up. I always try to keep an inventory of BB ply so i had really nothing to loose because as 5/8's said I have been using the TD designed LAB12 sub for some time, and I have a few spare lab12 speakers. I have been needing a smallish type sub for or mini array system, and I have now done 2 shows with the Pal12's. The first was a dance show in a new to me theater and I only had 2 subs built for that show. I had plenty of low for that hall and I would say they out preformed my double 18 boxs by far. The show I did last weekend was for a couple of live bands and I had 4 boxes for that gig. I still need more time with the subs but so far I have no complants. Small, strong down to 35hz and very compact. I used a yamaha pc 4800 amp and I never saw the meters get up to yellow, no speaker strain, no gak, just alot of clean lows. I would be curious to find out what the ohms of the speaker in this box is, I know that the ohms do change in the LAB12 so just wondering.
I am going slow with these box's but so far so good
Thank you for your work, and my back thanks you.
 

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Hi yodarocketdog,

I tried to enter the PAL12 into Hornresp from the drawing as a 3-fold and as a 4-fold. The electrical impedance plots overlay. I'll attach two plots, one with the range set to 100 Ohm max, and the other one with the range set to 10 Ohm max.

Regards,
 

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The "mini ray" box on the top has 2 5" 5N155 BMS speakers and 1 4510ND BMS line array driver. The fs on the speaker is around 60 hz although I have never felt confortable using them that low, they could do it. I am still playing around with the crossover points but you are right it is around 120 hz for the 2 shows I have done with the PAL 12. The next thing I want to try is to use the PAL 12 for a drum sub, the next festival we do we can do that so I am going to try. I will report back. View attachment 356539
 

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Finally got a chance to use them last night. We set up in a smallish venue, basement type place. They rocked for sure! If someone told me that there were only 2 12's in that venue for sub duty, I would have NEVER believed them. Very Impressed with them, and getting them up and down the stairs was no problem at all. The amp rack was much harder to carry around than these subs were.
Anyone thinking about building these, DO IT!

That said, I think I would like two more for more headroom. Maybe in the next few months ill build a couple more :D