OTop12 Build Thread

[Bruce Weldy]

When you get done with your painting put a piece of plastic wrap on the surface of the paint before sealing the can. It will keep it from skimming the top which is a pain to get out of the can.

While that's not a bad idea, I've had Duratex sit for a year then open it up. Just like the day I got it. Pretty amazing stuff.

[miked]

I spent the entire day in the garage with just breaks for food and a quick trip to Lowes (you always run out of something...today it was glue sticks). I wound up taking off about 3/4s of the piezo elements, grinding down the offending mounting ears and reinstalling before wiring. I did make wiring a lot easier, so I highly recommend getting the elements aligned correctly from the get-go as opposed to doing it my way and wasting 3 hours. There are just THREE things left to do; build and install the crossovers, install the woofers, wire it up to the rear jacks. I'm shot, so I'll let the pics do the talking.

Diffusers installed.



Melded arrays wired. What a PITA this was. I sure hope the payback on the melded vs. straight arrays is worth the hours I spent. BTW: ALL arrays were tested prior to installation. As far as I can tell, all elements are working.



All arrays were installed with quick disconnects, which were properly crimped and then heat-shrinked. I did this w/serviceability in mind. Soldering would be better, but if I ever need to remove the array, this will help greatly. The wires feeding the array were also hot-glued in place; there will be no wires flopping around in the breeze, so the disconnects wont' be moving. They aren't going anywhere.





Something you don't see everyday; the rear of a melded array through the baffle.


And....done. Of course, they'll look much better with grills and corners. Coming soon.







Lonely back panels, waiting to be called to active duty.


Trying to fit the crossovers (both) on a 5x6 board is not turning out to be easy. I keep toying w/the idea of separating them into two boards, but I really want them both on one board. Less wiring mess that way. I'm done for the night. Thanks for looking!

[88h88]

I sure hope the payback on the melded vs. straight arrays is worth the hours I spent.

Totally worth it. You've done a really nice job on this build buuuuuddy.

[miked]

Thanks, 88h88. I think I've done OK, but the proof will be in the pudding when I fire them up this week. Got family obligations to take care of today, so I'll be lucky to get the crossovers laid out, boards drilled and at least the components hot glued/zip tied down. Probably won't get that far though. Needless to say, I am really looking forward to getting them done and HEARING THEM. I may not have any Titans to go with them (yet) but at least I have some subs to use. Not BFM, but they get the job done.

In other news, last night I came up with a brilliant (in my small brain, anyway) idea for stands. I've been tossing ideas around for almost as long as I've wanted to build OTops. I really wanted to get some metal stands fabbed up, ala PulseMan's awesome stands, but that is just not financially possible at this time.

My idea is relatively cheap, will look good and will be VERY, VERY sturdy (2 "very's" for emphasis); that is very important to me. How sturdy? "Sturdy" as in "Nothing short of a 60mph wind or 180-pound drunk dude crashing into them is going to knock them over."

Additionally, I already have much of the materials needed and the total cash outlay will be less than $150. There'll be a separate complete build thread (vs. an "in-progress" thread) in this forum when they are done, which should be by next weekend. No more hints as I'm not giving the idea away...you'll have to wait and see the final product. Nothing groundbreaking; i.e. it's been done before, but not quite like this.

[Grant Bunter]

Pulseman's idea is awesome.

You can also achieve a slightly less industrial option with 2 regular stands side by side (ie for two sides you need 4 stands) and a platform with 2 regular tophats on it to attach it to the stands. Then strap your cabs to the platform.

I think Donny (Doncolla) does it this way and has pics somewhere.

It's worth a thought, and one day it will be how I do it too...

[miked]

Pulseman's idea is awesome.

You can also achieve a slightly less industrial option with 2 regular stands side by side (ie for two sides you need 4 stands) and a platform with 2 regular tophats on it to attach it to the stands. Then strap your cabs to the platform.

I think Donny (Doncolla) does it this way and has pics somewhere.

It's worth a thought, and one day it will be how I do it too...

Well, there goes my big secret, down to the last detail. Thanks a lot, Grant. LOL! That's exactly what I'm doing. The majority of the expense is from the additional two stands I had to buy. A single tophat barely cuts it for one of these cabs (IMO), let alone 2. Whereas your average commercial top is tall and narrow, these are short and squat and have much more side-to-side "rocking weight" if you will. Platform mounting is definitely the way to go. Getting two stands ala PulseMan done up would cost almost as much as the four OTops...I just can't swing it. Plus, the setup/teardown has opportunities for things to go wrong. I.E. You'd always have to carry additional nuts/bolts/washers...just more stuff to lose. Not only is a platform supported by two stands very stable, it makes a nifty place to hang lights from, too.

More to follow. Still trying to get the crossovers laid out. I think I've got it, but am double checking things.

[DJPhatman]

Still trying to get the crossovers laid out. I think I've got it, but am double checking things.

Post a picture of your lay-out. A picture is worth a thousand words!

[Grant Bunter]

Well, there goes my big secret, down to the last detail. Thanks a lot, Grant. LOL!

Not only is a platform supported by two stands very stable, it makes a nifty place to hang lights from, too.

Now there's an idea I did not think of, good one!

[Bas Gooiker]

Can't you just make some support for your platform out of pieces of trussing? Very sturdy and easy to setup.

[miked]

I guess I could, but; I don't own any trussing, I can't weld (and don't own any welding equipment) and anything that has to be bolted together...has to be bolted together. Anything I tried to make out of metal would look "cobbled together" and probably wouldn't be safe.

Don't get me wrong; in my perfect world I'd have Pulseman's stands. But being that I don't do the DJ/live sound thing for a living, I can't see spending that kind of coin to have metal stands fabbed up, when I have an equivalent solution "at hand."

For me, it was quicker, easier and cheaper to just buy two more stands and two, 2'x4', 3/4" oak plywood to make the platforms from. I already had the tophats as I'd originally planned on installing them in the OTops proper. The build will require more wood than just those two sheets of ply, but I have plenty of scraps in the shop to use.

The stands I'm using (On Stage Stands SS7725B) are rated at 120 lbs capacity each. I take that with a grain of salt; figure 100 lbs each. Two stands give a capacity of 200 lbs. Two OTops (Delta Pro loaded) will be roughly 50 pounds each. Plus another 20 for the platform. That's 120 lbs, leaving me at least 80 pounds of wiggle room...figure a scanner-type light hanging under each platform...another 20 pounds. Still got 60 to play with. Sure; two stands per side takes up more room and leaves another 3 legs to trip over, but the stands' legs will be "interwoven" if you will...the additional footprint isn't all that much larger and the advantages in safety and stability will be well worth it.

I ran out of time last night; I wanted to take a pic of my proposed xover layout...I am 99% sure I got it right. It looks ugly, but it should work. The PITA detail is on the positive side of the high pass circuit. The capacitor, coil, 30 and 4 ohm resistors all have to be soldered together, basically. Not sure what the best way to do that is. I have a high-temp soldering iron, but am worried about damaging components with all that heat applied for a long time. Hope that makes sense. I may clip an alligator clip in there to use as a heatsink. Any tips would be appreciated.

I would really like to get the crossovers at least laid-out (mounting boards drilled, etc) tonight.

[Tom Smit]

Not sure what the best way to do that is. I have a high-temp soldering iron, but am worried about damaging components with all that heat applied for a long time. Hope that makes sense. I may clip an alligator clip in there to use as a heatsink. Any tips would be appreciated.

Start by having the components wired together. Then, with the soldering iron turned on and the tip in mid-air, occasionally touch the solder to the tip. When the solder melts on the tip (may take a few moments), then bring the tip against the connection and dab the solder wire onto the tip causing the solder to run down onto the connection. This part should take a max of three seconds.

[miked]

Ah, similar to what I did when wiring the arrays. Thanks, Tom. Sooo close at this point...can't wait to fire'em up!

[miked]

Well, four hours and one burnt finger later, the crossovers are done. They won't win any beauty contests, but they're solid. I tested the first one I did with (all) four tweet arrays and it was good to go. No time to test the other three and right now I don't remember which one was the first one finished...so I've got to test them all tomorrow with at least one tweet array and a woofer (woofs not mounted yet). Got to test them before mounting them. I've never done crossovers without a PCB before...and probably won't again. LOL! I opted to have in/out pigtails to make wiring into the cab easier. Still undecided if I'll use quick disconnects (crimp on) or just solder to the wires in the cab. Feel free to voice your opinion on that, please. Pics and I'm done.

I have separate hot and ground wires for the lowpass/highpass filters, though they will share a common feed on the input side.






Reverse angle to see the connections.


RE: Wiring the tweets. The tweets have to be wired out of phase, correct? I should just connect the + from the tweets to the - output of the xover and - from the tweets to the + of xover, correct?

[gdougherty]

Don't have pictures, but I found 6 position screw down terminal strips at Home Depot that made wiring of the crossover components much easier. There's an input pair, LF pair and HF pair with an input and output side to each. I did all the filter cabling on one side and the jack and driver cabling on the other. It's a very simple matter to unscrew anything I need in order to pull it. On the few occasions I've opened up the cab during repaints or upgrades it was most handy to pull the leads to the back panel.


Edit: Something like this: http://www.allelectronics.com/make-a-st ... AMP/1.html

[Grant Bunter]

If you can, rotate the larger inductor about 20 degrees clockwise, so that it ends up perpendicular to the smaller inductor.
It wouldn't be an issue if the 2 inductors were more than 6 inches apart, but since that's not the case, best to do it now. It stops some sort of interference...