Radian's SLA Pro 4x6 build

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Radian
Posts: 2028
Joined: Tue Jul 29, 2008 12:56 pm
Location: Tucson, AZ

Radian's SLA Pro 4x6 build

#1 Post by Radian »

Just over a decade ago, Bill released plans for the SLA Pro and I got in on some Alphalite 6A's just before neodymium prices flew the coop. I sat on the drivers for what seemed an eternity, as life happens, eventually getting around to assembling everything.

It's been a helluva journey thus far. Here's the result of the build over the years.

The dry fitting, a crucial step:
SLAPro1.jpg
Last edited by Radian on Mon Jul 13, 2020 1:21 am, edited 1 time in total.
Good food, good people, good times.

4 - AT
1 - TT
1 - THT Slim
2 - SLA Pro 4x6 Alphalite

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Radian
Posts: 2028
Joined: Tue Jul 29, 2008 12:56 pm
Location: Tucson, AZ

Re: Radian's SLA Pro 4x6 build

#2 Post by Radian »

Milling out and test fitting the SpeakON jacks. I glued another piece of 15mm behind the terminals to add some strain relief. Neutrik STX hardware:
SLAPro14.jpg
Good food, good people, good times.

4 - AT
1 - TT
1 - THT Slim
2 - SLA Pro 4x6 Alphalite

User avatar
Radian
Posts: 2028
Joined: Tue Jul 29, 2008 12:56 pm
Location: Tucson, AZ

Re: Radian's SLA Pro 4x6 build

#3 Post by Radian »

Gluing up. Although these panels are all 90 degree cuts, ensuring that everything is dead nuts square is still no less important than any other cab build. All too easy to pick up a twist on the long side:
SLAPro10.jpg
Last edited by Radian on Mon Jul 13, 2020 3:21 am, edited 1 time in total.
Good food, good people, good times.

4 - AT
1 - TT
1 - THT Slim
2 - SLA Pro 4x6 Alphalite

User avatar
Radian
Posts: 2028
Joined: Tue Jul 29, 2008 12:56 pm
Location: Tucson, AZ

Re: Radian's SLA Pro 4x6 build

#4 Post by Radian »

Adhesive cured, round overs done, holes and imperfections filled. Everything finish sanded. Test fitting hardware prior to paint:
SLAPro2.jpg
Good food, good people, good times.

4 - AT
1 - TT
1 - THT Slim
2 - SLA Pro 4x6 Alphalite

User avatar
Radian
Posts: 2028
Joined: Tue Jul 29, 2008 12:56 pm
Location: Tucson, AZ

Re: Radian's SLA Pro 4x6 build

#5 Post by Radian »

Figured I'd knock out cables and finish the amp racks while waiting for the cabs to return from paint. Yeah, the amps are "old school" but they're long paid for, still sound great, and that Venu 360 is no joke :wink: ...neither is 10-2 SJOOW for that matter. Assembling those 90-degree connectors with that wiring was a PITA. From here on out, I'll stick to 12-4 and just solder the ends together.
Cables2.jpg
Cables1.jpg
Amps1.jpg
Amps2.jpg
Last edited by Radian on Mon Jul 13, 2020 3:27 am, edited 1 time in total.
Good food, good people, good times.

4 - AT
1 - TT
1 - THT Slim
2 - SLA Pro 4x6 Alphalite

User avatar
Radian
Posts: 2028
Joined: Tue Jul 29, 2008 12:56 pm
Location: Tucson, AZ

Re: Radian's SLA Pro 4x6 build

#6 Post by Radian »

Back from paint. Big shout out to Line-X of Tucson! :cowboy: Installing terminals, corners, feet, and pole mount:
SLAPro4.jpg
Good food, good people, good times.

4 - AT
1 - TT
1 - THT Slim
2 - SLA Pro 4x6 Alphalite

User avatar
Radian
Posts: 2028
Joined: Tue Jul 29, 2008 12:56 pm
Location: Tucson, AZ

Re: Radian's SLA Pro 4x6 build

#7 Post by Radian »

With the pole mounts installed, taking a test drive on the stands. These are K&M 21300's coupled with their ring-locking tilt connector and leveling leg. Upon delivery, felt the hand crank feature might be a little overboard. Ended up keeping them though as it makes positioning the cabs vertically a benign affair. I can't imagine trying to shoulder press their rated load:
Fly1.jpg
Last edited by Radian on Mon Jul 13, 2020 3:29 am, edited 1 time in total.
Good food, good people, good times.

4 - AT
1 - TT
1 - THT Slim
2 - SLA Pro 4x6 Alphalite

User avatar
Radian
Posts: 2028
Joined: Tue Jul 29, 2008 12:56 pm
Location: Tucson, AZ

Re: Radian's SLA Pro 4x6 build

#8 Post by Radian »

IMO, the biggest PITA of this entire project. I wasn't thrilled about having to build my own drivers. It's a huge time suck even for a DIY project, and COTS is my normal go-to, but the allure of the piezo sound got the best of me. Plan ahead. Test fit everything. Fortunately, PE sent me a flawless batch of Goldwoods, and an afternoon in the CNC lab turned out perfectly milled tweeters that made final assembly a breeze. A big shout out to Xerocraft Makerspace for saving the project. These melded arrays are a very tight fit (particularly with the Line-X coating applied) and the finished assemblies rather delicate until installed:
SLAPro5.jpg
Last edited by Radian on Mon Jul 13, 2020 3:30 am, edited 1 time in total.
Good food, good people, good times.

4 - AT
1 - TT
1 - THT Slim
2 - SLA Pro 4x6 Alphalite

User avatar
Radian
Posts: 2028
Joined: Tue Jul 29, 2008 12:56 pm
Location: Tucson, AZ

Re: Radian's SLA Pro 4x6 build

#9 Post by Radian »

Ordered 6mm perforated grill stock from PE, which paired nicely with their acoustic grill foam. Unfortunately, due to a minor bending error they didn't fit so well on the baffle once the drivers were installed. Clearance between the drivers and the sides of the cabs is tight. 1/4" too short in width and the grills were sitting on top of the drivers rather than along the baffle as intended. Regardless, I liked the finished result and will eventually source fitted replacements. Could just be me, but I swear they sound a little better with the grills installed too:
SLAPro6.jpg
SLAPro7.jpg
SLAPro8.jpg
Good food, good people, good times.

4 - AT
1 - TT
1 - THT Slim
2 - SLA Pro 4x6 Alphalite

User avatar
Radian
Posts: 2028
Joined: Tue Jul 29, 2008 12:56 pm
Location: Tucson, AZ

Re: Radian's SLA Pro 4x6 build

#10 Post by Radian »

Wiring everything up. Once again, an ounce of planning goes a long way here. Even though I got the polarities right, I botched the routing. :bash: I'll be dipping back into these tomorrow to re-plumb the woofers in a more sensible way before adding the stuffing for final assembly:
SLAPro15.jpg
Good food, good people, good times.

4 - AT
1 - TT
1 - THT Slim
2 - SLA Pro 4x6 Alphalite

User avatar
Radian
Posts: 2028
Joined: Tue Jul 29, 2008 12:56 pm
Location: Tucson, AZ

Re: Radian's SLA Pro 4x6 build

#11 Post by Radian »

Everything plumbed together and it's time for a test drive at low power to QC the electronics:
SLAPro11.jpg
Good food, good people, good times.

4 - AT
1 - TT
1 - THT Slim
2 - SLA Pro 4x6 Alphalite

User avatar
Radian
Posts: 2028
Joined: Tue Jul 29, 2008 12:56 pm
Location: Tucson, AZ

Re: Radian's SLA Pro 4x6 build

#12 Post by Radian »

Finished weight of the cabs (Baltic Birch) with the Alphalite drivers, minus the steel grills. Figure another pound for those. For comparison, I've got a pair of Klipsch HIP that check in at a toe-crushing 65 lbs...each :shock: These are a dream to place on stands.
SLAPro16.jpg
Good food, good people, good times.

4 - AT
1 - TT
1 - THT Slim
2 - SLA Pro 4x6 Alphalite

User avatar
Radian
Posts: 2028
Joined: Tue Jul 29, 2008 12:56 pm
Location: Tucson, AZ

Re: Radian's SLA Pro 4x6 build

#13 Post by Radian »

Now for some crappy iPhone recorded videos. These will be available to the forum only temporarily, until final assembly and a I find a better place to shoot. The drivers are only tacked in place, no sealant, and no stuffing. What's the point, right? Just ringing them out briefly to confirm the wiring and listen for any gross errors. :noob: Not gonna lie, my iPhone can't record audio for shit. The case makes it sound like a tin can, and there's this "grit" that sounds like heavy static for whatever reason. Regardless, you should still be able to tell there's some serious potential in this design once all the details are complete. Totally worth the journey as the next available option is easily 4x the cost.

Good food, good people, good times.

4 - AT
1 - TT
1 - THT Slim
2 - SLA Pro 4x6 Alphalite

User avatar
Radian
Posts: 2028
Joined: Tue Jul 29, 2008 12:56 pm
Location: Tucson, AZ

Re: Radian's SLA Pro 4x6 build

#14 Post by Radian »

Test drive up on the pole. Checking out the pattern through about 90 degrees. If you can figure out a way to fly these things, it's definitely the way to go. 3 meters up and 15 degrees tilted down in this shot. I cannot wait to get these things finished! :hyper:

Good food, good people, good times.

4 - AT
1 - TT
1 - THT Slim
2 - SLA Pro 4x6 Alphalite

Bruce Weldy
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Joined: Fri Nov 27, 2009 11:37 am
Location: New Braunfels, TX

Re: Radian's SLA Pro 4x6 build

#15 Post by Bruce Weldy »

Congrats! Excellent work.

6 - T39 3012LF
4 - OT12 2512
1 - T24
1 - SLA Pro
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

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