J15L

[ncgrove]

I'm going to go ahead and start my J15L build thread. It might take a while to finish, as I'm working on a J10L as well. I haven't seen a J15L build on here, so maybe this will help you decide if you want to make one. I already have a standard J15 for a bass cab, so I'm trying to drop a few lbs.

Here's the horn brace layout steps. Draw a giant circle, with a smaller circle inside of it. There's supposed to be an even smaller circle inside of the two, that's used as a driver-side phase plug extension. I'm foregoing this step and going with an all-foam phase plug extension to maybe save some weight, as well as jig saw aggravation.



With an addition of an octagon, the smaller circle turns into half of a driver spacer. The horn braces are laid out with the framing square, and lightening triangle notches are drawn. I managed to fit 6 horn braces (the plans call for 5) around the circle, which is nice. I'll have a sort of awkward-shaped piece of ply left over, so I'm going to lay out 4 individual horn braces without having to draw another huge circle. That means I'll have to make the other half of the driver spacer on another sheet of 1/4" ply, but I have a whole virgin sheet to use.



Here's a close-up of one of the horn braces. It might be difficult to appreciate the scale on the close up, but these are going to be some pretty big braces. If you've seen a regular J15 I'm sure you can understand the scale.



That's all I have for now. Hopefully I'll have something else of interest to post soon.

-Nathan

[ncgrove]

I spent a whole lot of time the past few days with the pencil, framing square, and jig saw. I got the top/bottom, sides, baffle, and the horn sheath braces all laid out and cut. I learned from my J10L build that it's a good idea to draw out the positions of all pieces that are going to be attached to the top/bottom before anything is put together to keep everything square and in place. And then draw everything on both sides of each board, so that you'll know where to shoot brads. Here's some top/bottom pictures:





Same idea with the baffle. I marked where the horn sheath braces will attach to the baffle, as well as the 1/8" brace offset to allow for the horn and throat sheaths.





You can see there is a whole bunch of measuring and drawing before the PL even gets taken out. I think it's completely worth all the effort, as it's pretty difficult to measure and draw once things inside the box start to get in the way of framing squares and speed squares.

I just noticed I didn't take any pictures of the sides or horn sheath braces. I'll do that tonight and amend this post if I can remember.

-Nathan

[ncgrove]

I finally got a little bit of work done on this front. I looked through my previous post and noticed that I didn't drill the vent holes in the baffle. I'm glad I saw, because it would have been a real pain to drill these later. Here's the baffle complete with vent holes:



I also got the first pair of horn braces installed on what's either going to be the top or the bottom. They were a bit long, so a little bit of sanding was required to get them to fit. I used the standard techniques with guide board and 1/4" offset jig. Piece of cake.





I came across what I thought was a good idea for keeping PL off of the guide board. I was getting pretty frustrated trying to keep waxed paper on the guide board from getting in my way, so I just put masking tape along the parts that were going to see any adhesive. It's easy to get the masking tape in place, and easy to take off. No PL on my favorite guide board!

[Bas Gooiker]

Looking forward seeing your J15L come together. I can't remember seeing one being done before.

Good luck!

[ncgrove]

Progress on this is going painfully slow. I stapled the braces to the other top/bottom last night. It looks exactly the same as the previous picture, but I thought I'd post a picture to keep yall (and myself) interested:



I hope I can make more progress relatively soon.

[ncgrove]

FINALLY got some big work done. I tacked on the baffle and sides to the top/bottoms. Everything went well and it ended up being reasonably square. The J15L is a completely different animal than the J10L. The panels are huge, and a little difficult to manage. Here's the result:



Here's the backside:



I did all that yesterday, and let it sit overnight so that the PL would set up.

Today, it was time to tackle the braces, which were surprisingly easy. Here you can see me making sure the brace fits well:



They all fit well enough without any trimming. Here's me marking where to shoot brads from the side into the brace:



Now the trick is to tack the braces in place to the sides, and then the baffle, trying to keep everything square. And then repeat 5 more times. Here's after the first side was done:



And here's where it is now:



I'm going to let the PL on the braces set overnight before I start putting a lot of stress on them with the horn sheath. It's ok though. I've got a 12 pack, a J10L, and a pretty girl waiting for me at the pool. Good Friday, indeed!

Oh, and here's the obligatory picture of my workshop:



I've got a feeling there are 5 motorcycles in my future...

[Tom Smit]

I love your workshop!

[Chris_Allen]

There is some really good cutting on the baffle too. Nice accurate pencil lines, that's what we like to see!

The J15 looks like quite a big beast.

[LelandCrooks]

Nice. The J lites are a challenge. And worth the work.

[AntonZ]

Nice. The J lites are a challenge. And worth the work.

My thoughts exactly. There seems to be no love for my old OmniTop 12s, so I may tear them apart and build some J12 lites with those drivers and piezo's.

[biggerrigger]

Looking good man, Nice and tidy.

[sine143]

Nice. The J lites are a challenge. And worth the work.

My thoughts exactly. There seems to be no love for my old OmniTop 12s, so I may tear them apart and build some J12 lites with those drivers and piezo's.

how much for the empty boxes

[AntonZ]

Nice. The J lites are a challenge. And worth the work.

My thoughts exactly. There seems to be no love for my old OmniTop 12s, so I may tear them apart and build some J12 lites with those drivers and piezo's.

how much for the empty boxes

You are aware you are on a different continent?

[ncgrove]

Got the first horn sheath on today. Here's how it went:

I drew lines where the horn braces are so I'd more or less know where to shoot the staples:



I happened to have a scrap piece of 1/2" plywood that worked perfectly to hold the sheath tight to the braces on the baffle end. I used a shopping bag to keep the scrap piece from being glued in place. Here's a shot of me mocking it up to make sure everything was going to turn out ok. I found it's really important to take your time while doing the horn sheathes:



I used a copious amount of PL here, just to make sure everything will be nicely glued in place:



I put the sheath in place and snugged up the scrap jig. I then shot some brads through the jig and into the baffle to hold the jig in place:



Now it was fastening time. Here's a shot of the stapled sheath. I probably used more staples than needed. You can find a discussion of this on my J10L thread.



I scribed a line across the panel so I'd have a good idea of where to shoot staples into the sides:





Not the best staple job, but it'll do.

Here's a shot of the inside of the sheath. You can see plenty of PL squeeze-out, along with not terrible staple accuracy. I was pretty surprised! Moral of the story- take the time to measure and draw lines carefully. Actually, I wasn't all that careful on the horn sheathes, but it turned out ok.



Now it's time for crawfish boil!

[ncgrove]

Here's where it is now. Got the other horn sheath put on. It went just as well as the first, but I was a little hungover so it took a bit longer to do. I had to take a short break after every few staples. Gotta love the PL.



I held the horn sheath scrap jig in place with a few brads. My technique to get the scrap jig off is just to get a long skinny piece of 1/2" BB scrap, put it against the scrap jig, and give it a whack with a pipe hammer. One or two hits is all it takes. And nail holes in the baffle aren't a cosmetic issue because most of the baffle is covered up by throat sheathes or Styrofoam hemispheres.

Now the bummer is that I'm out of cut pieces, so I have to get the framing square, compass, and pencil back out and start laying out some more pieces. The horn sheathes really stiffened up the box, and it's starting to look pretty good too.

Thanks for looking.

-Nathan