OTop12 Platforms

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miked
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Joined: Fri Oct 23, 2009 4:18 am
Location: San Antonio, TX

OTop12 Platforms

#1 Post by miked »

Having recently completed 4 OTop12's (minus grills...currently ordered) I was in need of a way to mount them atop stands. I opted not to include a tophat inside my OTops due to balance issues. The only place to safely mount a tophat in an OTop is in the middle of the cab, poking up through the lower reflector. OTops are very back-heavy; even more so when you have the 16-pound Delta Pro 12 woofers like I do. With the tophat dead-center in the cab, the cabs would be unbalanced and wouldn't sit correctly on stands, especially stacking them 2-high.

The best way to mount OTops is to actually SIT them on all four feet, on top of a platform/scaffold-type "stand." Not being a welder and being short on cash, I had to think up a second-best, but still portable and strong, option. I built a platform with normal, 1-3/8" steel tophats mounted inside of it. The platform sits on TWO standard tripod stands, dividing the weight of two OTops (almost 100 pounds) between the two stands.

First, some build pics, then the finished product...or you could just be a party pooper and scroll down to get to the finished pics...but what fun is that? :cop:

Platforms are constructed of 3/4" oak ply on the top/bottom/front back with 3/4" "BC" plywood braces inside. Plenty of PL and 1.5" brads holds them together. You could park a bus on these things. Finished size is 4" thick x 22" wide x 19-1/2" deep. They weigh 19.3 pounds each (weighed on a digital postal scale).

Cut four boards to 18-1/2" x 21".
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Calculated the internal space needed for recessed tophats and cut my uprights to 2-3/4" high. Tophats were just sitting approximately where they'd be mounted...I was "eyeballing."
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Test fitting the top. Note the recesses in the top for the cab's feet to sit in. If you're thinking "Why, it's nothing more than a pallet, actually!" You'd be incorrect. It's a High-Speed Loudspeaker Placement Accessory. :mrgreen:
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Wanted to make sure the tophats had plenty of support and the mounting screws plenty of wood to bite into. Cut 5"x5" squares of 3/4" ply and PL'd/brad nailed in place. And yes; that bottom piece WAS going to be a top piece. Until I cut the 4 cab-foot receses in the wrong spots. Then the top became a bottom real quick. :bash:
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Chucked the 2" Forstner bit (IIRC it was 2") in the drill and bored the mounting holes.
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And we wind up with this.
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Realized that these would essentially be empty, reverberant boxes. So I lined them with mattress topper left over from the OTop build. Just stapled it in.
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PL'd the daylights out of them. Here they are, drying/curing. Note the diameter of the tophats traced on the bottom for recessing.
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I made a template for recessing the tophats...no pic of the template. After cutting the recesses, I realized the diameter of the tophat is larger at the bottom (at the mounting flange) and would not sit flush. So I had to route out additional material right at the opening.
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Tophats sit flush now.
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Then it was time to roundover the edges (3/8" roundover bit) and spackle, spackle, spackle.
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Lots of sanding, four coats of Duratex, corners and mounted hats later and tada!
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And the finished product/proof of concept. I only have two stands ATM; the other two (identical ones) are in the mail. Note that I chose these stands specifically b/c they have a steel pin that holds the pole up. The twist knob/friciton knob is only used to keep the pole from spinning. Stands are rated at 120 pounds EACH. So 120-ish pounds split b/t 2 stands should be cake.
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Camera was tilted. They don't lean this far foward IRL. I got the center of gravity almost perfectly centered over the tophats...could've been moved forward about another 1/2"-3/4" but "good enough" works too.
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I have black racheting tie downs in the mail as well. I was just testing it all out with these safety orange ones.
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With just one cab you don't need the tie downs at all. Of course, I'll use them anyway.
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Some notes: I just assumed that both tripod stands would "open and sit at the exact same height." They don't. Getting them to the same height takes a little work. Also, the tophats are 15-1/2" center-to-center in the platforms. Both stands need to be pretty much exactly that far apart, else they don't sit right. That said, with everything where it needs to be the platform is very stable and sits hard and firm. There is a little wiggle room inside the tophat. Though my hats are 1-3/8" and poles in the stands are 1-3/8" there's still some play. With two cabs mounted, the whole assembly will rock front/back maybe a 1/4" in each direction, but you really have to push on it. The STANDS however, do not move. I will set the whole thing up in the backyard this weekend and watch it all day while the wind blows. I do not think I'll need it, but possibly another strap or two anchoring the platform "fully rocked forward/backward" might be in order, but I doubt it.

So there you have it. I'm pleased with how they turned out. They were quick and cheap to build and get the job done. In the future, I'd still like to get collapsable stands like Pulseman's built, but that's down the road. For now, these fit the bill. Thanks for looking.

Grant Bunter
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Location: Ilfracombe Queensland Australia
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Re: OTop12 Platforms

#2 Post by Grant Bunter »

Hey mike,

:clap: :clap: :clap: bravo

Nice work, they look great :)
Built:
DR 250: x 2 melded array, 2x CD horn, March 2012 plans.
T39's: 4 x 20" KL3010LF , 2 x 28" 3012LF.
WH8: x 6 with melded array wired series/parallel.
Bunter's Audio and Lighting "like"s would be most appreciated...

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racertomtom
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Location: Southern, Illinois
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Re: OTop12 Platforms

#3 Post by racertomtom »

:clap: Great job!! As I am preparing to build O-tops myself, I appreciate the detail you put in your build threads. Thanks, and again, Great job on the O-tops and stands!
4 - WH8
2 - T39 24" Lab12
2 - OT12 3012HO/NSD2005

Bruce Weldy
Posts: 8585
Joined: Fri Nov 27, 2009 11:37 am
Location: New Braunfels, TX

Re: OTop12 Platforms

#4 Post by Bruce Weldy »

Nice job Mike.

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."

miked
Posts: 1209
Joined: Fri Oct 23, 2009 4:18 am
Location: San Antonio, TX

Re: OTop12 Platforms

#5 Post by miked »

Thanks for the kind words. Time will tell as to how well they hold up, but I overbuilt them, so all should be well. This weekend (or sooner if I'm able to) when I get both pairs of cabs setup in the backyard, I'll have a better read as to their stability. This is an untested (for me) concept so I want to see what effect a gentle breeze, a good wind and a good gust of wind have on them. In the garage, I sorta "pushed" and "knocked into" the cabs, just to see what would happen. Aside from the aforementioned slight back and forth rocking once or twice, nothing happened. Stands didn't budge, just the whole cab/platform assembly moved just a tiny bit.

I ordered the grills today and my other two stands made it to FEDEX today as well. I'll have the stands by Fri...we'll see about the grills. I want them "now" but wasn't paying $60+ for 2-day shipping.

gdougherty
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Re: OTop12 Platforms

#6 Post by gdougherty »

Like the look. Clean and solid. Especially like the recessed tophat flanges. That's something I didn't bother with in my build.

I can definitively say they are heavily overbuilt considering my original model was made from 3/8 ply sandwiching a 1x frame. The sides are made from 1x6 laying flat and the tophats pass through them while screwed into about 1.5" of wood between the plywood layers and the internal frame. Mine are also thinner as I didn't bother to enclose the tophats in the platform. I use the protruding tophat as extra assurance the cabs won't slide off sideways and the lip further past the tophat gave me a great place to mount some eyebolts in one of the tophat screw holes for securing the ratchet straps. Helps with a 3-4 high stack of OT's and not needing a super long strap. Weight on the Mk1 is about 4lbs, how much did those beasts come out to?

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Tom Smit
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Location: Sarnia, Ont. Canada

Re: OTop12 Platforms

#7 Post by Tom Smit »

Now that is "solid"! You could easily stack 6 cabs on those adaptor plates....they'll take it. Of course, you'd have to have differents stands then. Looks good though. :clap:
TomS

miked
Posts: 1209
Joined: Fri Oct 23, 2009 4:18 am
Location: San Antonio, TX

Re: OTop12 Platforms

#8 Post by miked »

@gdougherty: The platforms weigh 19 pounds each. The two tophats and metal corners alone are probably 4-5 pounds of that. I'd like to see pics of your platforms, particularly that eyebolt setup you mentioned.

@Tom Smit: I'd be nervous going more than 2-high. Just getting the 2nd cab up there was a wrestling match...it might've been easier if I used a real ladder instead of a plastic stepstool though. LOL!

biggerrigger
Posts: 560
Joined: Sun Jan 28, 2007 6:32 am
Location: ohio

Re: OTop12 Platforms

#9 Post by biggerrigger »

Great looking set of stand basses. Great workmanship.
Built
4-25" Lab12 loaded T39's
2-DR250's Melded array
2-DR250's Flat array

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shawn_g
Posts: 386
Joined: Sat Jan 14, 2012 9:00 pm
Location: Logan, OH

Re: OTop12 Platforms

#10 Post by shawn_g »

Looks great! Nice work.

Bruce Weldy
Posts: 8585
Joined: Fri Nov 27, 2009 11:37 am
Location: New Braunfels, TX

Re: OTop12 Platforms

#11 Post by Bruce Weldy »

Ok Mike, I've got a question for ya'.

How do you get 2 dozen pics in a single post? It always cuts me off at 4 or 5.

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."

Grant Bunter
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Joined: Mon Nov 28, 2011 11:12 am
Location: Ilfracombe Queensland Australia
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Re: OTop12 Platforms

#12 Post by Grant Bunter »

Bruce Weldy wrote:Ok Mike, I've got a question for ya'.

How do you get 2 dozen pics in a single post? It always cuts me off at 4 or 5.
Bruce,
Open a photobucket (or any of the other free image hosting sites) account. Play around with it some to learn how to upload an image (ie, by clicking upload lol)
When it is uploaded (and saved if necessary) it gives you a few options.
With photobucket, those options are on the right hand side of each pic.

You can copy (left click) then paste when you're typing, to post the [URL] if there is a limit to the images you can post here in the forum. This is what Mike used I think.

Or you can use the [IMG] tag (same way, left click to copy, then paste), which is what I do, but I rarely post more than a few images...
Built:
DR 250: x 2 melded array, 2x CD horn, March 2012 plans.
T39's: 4 x 20" KL3010LF , 2 x 28" 3012LF.
WH8: x 6 with melded array wired series/parallel.
Bunter's Audio and Lighting "like"s would be most appreciated...

Bruce Weldy
Posts: 8585
Joined: Fri Nov 27, 2009 11:37 am
Location: New Braunfels, TX

Re: OTop12 Platforms

#13 Post by Bruce Weldy »

Thanks Grant.

Not sure if that's not more work than just pulling it over from my hard drive. But, I may try it .....

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."

miked
Posts: 1209
Joined: Fri Oct 23, 2009 4:18 am
Location: San Antonio, TX

Re: OTop12 Platforms

#14 Post by miked »

Yep, Grant hit it; I use Photobucket. It is FREE and that's the best price of all. It is slightly more work; you have to resize the pics on your computer (b/c the BFM site has a 640-pixel wide limit on pics), upload them, then copy/paste the IMG tags one by one. The main advantage is that there's no limit to how many pics you can link in a single thread post. Also, the pics are hosted on a separate site and aren't going anywhere. I've got pics out there from the 2002-era. Also, Photobucket allows you to set albums as Public or Private.

gdougherty
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Re: OTop12 Platforms

#15 Post by gdougherty »

miked wrote:@gdougherty: The platforms weigh 19 pounds each. The two tophats and metal corners alone are probably 4-5 pounds of that. I'd like to see pics of your platforms, particularly that eyebolt setup you mentioned.
Stands
Stands
Nothing on the eyebolt that I could find. Pretty simple though. The tophats have 4 screw holes each 1/4 way around the flange. I took out one screw and replaced it with a hole drilled all the way through the platform for an eyebolt. The platform is sandwiched between a washer and nut on the top side and the flange and a nut on the bottom to keep it secure. My only complaint is the nut on the bottom which doesn't sit flush and pretty like your flanges. None of mine is flush or as pretty so I don't worry too much. I had a photo somewhere showing one OT12 strapped and hanging from the bottom of the platform and three stacked on top.

It cost a big chunk but I just recently upgraded to the Ultimate lighting stands that will go up about 8.5ft. Used those for the first time this weekend and it was all nice and solid. Now I'd like to swap the tophats for something in a bigger diameter since the pop-up extension on the stands leaves just a little wobble room.

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