Otop Jarray build x 4

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Tom Smit
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Re: Otop Jarray build x 4

#31 Post by Tom Smit »

himhimself wrote: Sat May 04, 2019 12:05 pm Actually probably was an unnecessary adventure as the cabinets seem to be more square than my skills warranted - Yay!
:clap:
TomS

himhimself
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Re: Otop Jarray build x 4

#32 Post by himhimself »

Thanks Tom. Pulled the clamps off cab 1 this morning and she's SOLID. Planning to get cab 2 sheaths glued up today and the throat reflectors on cab 1. Maybe the rear braces too - we shall see. Then going to have to take a break until at least Friday, unfortunately. But I'm getting there... I did a quick test fit of my tweeter arrays and realized I will need to trim a bit off the top and bottom to get them in there. I knew it was going to be real close when I made them, since they were each a little tall after the longwise cuts. Oh well, no big deal with that. And it all will get hidden behind a grill anyway.
2xT30 (20", 3012LF)
2xT30 (21", 3012LF)
4xOtop J-array (Beta12, melded/straight piezos)
Truck Tuba (MCM)
Next up: 2xJack12 or family of table tubas

himhimself
Posts: 599
Joined: Fri Nov 13, 2015 9:34 pm
Location: Vancouver BC & Bloomington IN

Re: Otop Jarray build x 4

#33 Post by himhimself »

Just glued sheaths onto cab 3 and reflectors on cab 2.
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2xT30 (20", 3012LF)
2xT30 (21", 3012LF)
4xOtop J-array (Beta12, melded/straight piezos)
Truck Tuba (MCM)
Next up: 2xJack12 or family of table tubas

himhimself
Posts: 599
Joined: Fri Nov 13, 2015 9:34 pm
Location: Vancouver BC & Bloomington IN

Re: Otop Jarray build x 4

#34 Post by himhimself »

Clamps off cab 3 and onto cab 4 now. From the backside, one of the sheaths on cab 3 was gapped out a little from the braces in the middle so I filled in with some PL. Should be fine. I did not brad nail or staple the sheaths while bending them into place, so that is probably why. My method was to put the narrow sides down into the PL against the baffle, push wedges between to hold them snug, fire a few pins into the center two braces near the baffle to secure them, push the larger wedge in (between the sheaths and the middle two braces), fold the sheath over the braces and then clamp to the edge. The first time I tried without pinning the center and realized the sheaths wanted to slide up and away from the baffle when clamping the edges. It always gets easier by the time I move on to the later cabs...but I am sure I will forget many of the little tricks by the time I go to build my next set :roll:
2xT30 (20", 3012LF)
2xT30 (21", 3012LF)
4xOtop J-array (Beta12, melded/straight piezos)
Truck Tuba (MCM)
Next up: 2xJack12 or family of table tubas

himhimself
Posts: 599
Joined: Fri Nov 13, 2015 9:34 pm
Location: Vancouver BC & Bloomington IN

Re: Otop Jarray build x 4

#35 Post by himhimself »

Cut the ports today - thanks to Leland and the pattern following router tutorial. Tomorrow I'll pull the clamps on cab 4 and get the reflectors installed.
Attachments
15576217796994059328226943731128.jpg
2xT30 (20", 3012LF)
2xT30 (21", 3012LF)
4xOtop J-array (Beta12, melded/straight piezos)
Truck Tuba (MCM)
Next up: 2xJack12 or family of table tubas

himhimself
Posts: 599
Joined: Fri Nov 13, 2015 9:34 pm
Location: Vancouver BC & Bloomington IN

Re: Otop Jarray build x 4

#36 Post by himhimself »

Cut and drilled a bunch of little squares for the side bracket t-nuts. Spade bits make such a mess when the come out the back side of plywood. Pounded through about half of the t-nuts. The three spikes make a mess coming out the back too. I've just been using a tiny screw driver to pick all the splinters away so they will pull nicely into the back of the sides when I install them later. I also used a forstner bit I had laying around to take off one ply so the body of the t-nut insets a touch and should let the backer piece glue up tighter.
Not sure why, but I'm paranoid about trimming off the edges of the sheaths. Hopefully that will all go smoothly next week.
2xT30 (20", 3012LF)
2xT30 (21", 3012LF)
4xOtop J-array (Beta12, melded/straight piezos)
Truck Tuba (MCM)
Next up: 2xJack12 or family of table tubas

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Tom Smit
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Location: Sarnia, Ont. Canada

Re: Otop Jarray build x 4

#37 Post by Tom Smit »

himhimself wrote: Sat May 11, 2019 7:52 pm Cut and drilled a bunch of little squares for the side bracket t-nuts. Spade bits make such a mess when the come out the back side of plywood.
What you could do is when the point goes through the other side of the material and the the hole is partly drilled, then stop drilling and start from the other side where the point had come through.
himhimself wrote: Sat May 11, 2019 7:52 pmPounded through about half of the t-nuts. The three spikes make a mess coming out the back too. I've just been using a tiny screw driver to pick all the splinters away so they will pull nicely into the back of the sides when I install them later.
Predrill the holes for the spikes. :)
himhimself wrote: Sat May 11, 2019 7:52 pmI also used a forstner bit I had laying around to take off one ply so the body of the t-nut insets a touch and should let the backer piece glue up tighter.
Good job!
himhimself wrote: Sat May 11, 2019 7:52 pm Not sure why, but I'm paranoid about trimming off the edges of the sheaths. Hopefully that will all go smoothly next week.
Hey, you'll get it done. :clap:
TomS

himhimself
Posts: 599
Joined: Fri Nov 13, 2015 9:34 pm
Location: Vancouver BC & Bloomington IN

Re: Otop Jarray build x 4

#38 Post by himhimself »

Up early helping kids make breakfast for mom, then pulled the big clamps off cab 4 and glued in the reflectors. That's prolly it for today.
Thanks for the tips, Tom.
2xT30 (20", 3012LF)
2xT30 (21", 3012LF)
4xOtop J-array (Beta12, melded/straight piezos)
Truck Tuba (MCM)
Next up: 2xJack12 or family of table tubas

himhimself
Posts: 599
Joined: Fri Nov 13, 2015 9:34 pm
Location: Vancouver BC & Bloomington IN

Re: Otop Jarray build x 4

#39 Post by himhimself »

Cut the edges of the sheaths
Attachments
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2xT30 (20", 3012LF)
2xT30 (21", 3012LF)
4xOtop J-array (Beta12, melded/straight piezos)
Truck Tuba (MCM)
Next up: 2xJack12 or family of table tubas

himhimself
Posts: 599
Joined: Fri Nov 13, 2015 9:34 pm
Location: Vancouver BC & Bloomington IN

Re: Otop Jarray build x 4

#40 Post by himhimself »

Was paranoid about how to do this. I played around with the circular saw sled thing I had made, and couldn't find a good way to clamp it or hold it and was afraid I'd slip and slice into the cabs or otherwise screw something up. So I finally just scribed a line down each face and cut carefully with a hand saw, then finished up with my belt sander. Worked fine. Oh, to have more time to dedicate and get these things done...
2xT30 (20", 3012LF)
2xT30 (21", 3012LF)
4xOtop J-array (Beta12, melded/straight piezos)
Truck Tuba (MCM)
Next up: 2xJack12 or family of table tubas

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Bill Fitzmaurice
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Re: Otop Jarray build x 4

#41 Post by Bill Fitzmaurice »

Screw the sled to the cabinet, fill the holes when you're done.

himhimself
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Joined: Fri Nov 13, 2015 9:34 pm
Location: Vancouver BC & Bloomington IN

Re: Otop Jarray build x 4

#42 Post by himhimself »

Thanks Bill. With 1/4 panels, I didn't want to screw into the edges. Anyway, handsaw worked fine for me.
Glued in the braces on the back side of the baffle. The hot melt glue trick was sweet, definitely will keep that in the arsenal. Glued up the 32 little tee-nut deals too. Not perfect but will work and be unseen anyway. Next up I need to laminate some strips for my tweeter mounts and back flanges while the boxes cure up tonite.
it's amazing how light and stiff these boxes are turning out.
2xT30 (20", 3012LF)
2xT30 (21", 3012LF)
4xOtop J-array (Beta12, melded/straight piezos)
Truck Tuba (MCM)
Next up: 2xJack12 or family of table tubas

himhimself
Posts: 599
Joined: Fri Nov 13, 2015 9:34 pm
Location: Vancouver BC & Bloomington IN

Re: Otop Jarray build x 4

#43 Post by himhimself »

A view of the braces I just glued in.
Attachments
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2xT30 (20", 3012LF)
2xT30 (21", 3012LF)
4xOtop J-array (Beta12, melded/straight piezos)
Truck Tuba (MCM)
Next up: 2xJack12 or family of table tubas

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Bill Fitzmaurice
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Re: Otop Jarray build x 4

#44 Post by Bill Fitzmaurice »

All those hours I spent building balsa wood model airplanes in my youth weren't wasted.

himhimself
Posts: 599
Joined: Fri Nov 13, 2015 9:34 pm
Location: Vancouver BC & Bloomington IN

Re: Otop Jarray build x 4

#45 Post by himhimself »

Tweeter array supports are now in place. A little fiddly to get right, as I used them to help straighten out the tops and bottoms too. I drilled a few little shallow holes in the ends, scarred the mounting spots on the panels, wet them a touch, then positioned them and drove a few pins in. Rock solid! One thing I luckily figured out - as I was fitting them and checking with the piezos, it seemed the melded arays had a lot more support showing on the sides than the straight, so I thought, I'll just put them a little closer together. However, any closer together and it's not possible to fit the driver portion through. Glad I didn't glue them up that way. Follow the plans!!!!
Handle backers are tacked in and curing right now. Had a scrap of weird trim lying around that I ran lengthwise through the table saw to remove some of the profile. I like the way it feels. It's a little thicker and I think it helps since the sides are only 1/4" to begin with. I'll post a picture shortly...
2xT30 (20", 3012LF)
2xT30 (21", 3012LF)
4xOtop J-array (Beta12, melded/straight piezos)
Truck Tuba (MCM)
Next up: 2xJack12 or family of table tubas

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