BillFitzmaurice.info

Has it really been that long since I posted about my DRs?

I finally made some more progress. I did the layout on all of the tops and bottoms, and then routed out the two semicircles using a circule guide for my router/
Four pieces, Eight semi-circles, and here we are:
I think I'm stuck at this point - the plans call for a cut in the bottom for the movable tophat, but I feel I should have one of those in hand before cutting, and I need a driver before cutting the woofer anchor. When I just stacked the baffle and a top and bottom together I can see how big this is going to be. Perhaps I really wanted DR200s, but I'll keep going along this path. I also see why the 280s are not a one-man lift.

Some household construction has been keeping me out of my workshop, but I'm gearing up to do some construction over winter break. I just ordered all of the remaining parts for the DRs, and once I have those tophats and drivers in hand, I'll be able to complete the next steps.

Hi Billkatz

The Top Hat can be mounted any time, the only real risk of fitting it once the box is complete or at least advanced in the construction, is that if you make a mistake you can't just throw away the piece and start again . With regards placement there is really only one place it can go and it looks to me to be pretty close to the centre of gravity of the box anyway. My boxes are complete and I have ordered the Top Hats. Hopefully I'll have them next week and will post how I go fitting them (let's hope I don't have to eat my words )
With regards the woofer spacer, I personally cant see any reason why you could not fit it later in the construction. You can continue till the step of fitting the sheaths on the woofer assembly. That will allow you to keep going with the construction of the High Frequency module as well. There is plenty of room for clamps etc untill the sheaths are on.

Cheers S

I finally got back to working on my DRs. The Jasper jig works great for cutting the woofer holes. My other router jig wouldn't cut holes small enough (it worked for the 12" woofers on the Titans, but not the 10" drivers on the DR250). I drilled pilot holes, and ran a Recex screw in each of the holes, so I'm ready to mount woofers. Except that I need throat reducers, and Leland doesn't make them at the moment. So I need to go out and buy some 1" solid foam. I hope it is sold in something less than 4x8 sheets for the couple square feet that I need.

I tried using the Kreg jig to make pocket holes on the woofer baffle, but the screws didn't pull things tight, so I reverted to clamps and the brad nailer.

Here's the first side clamped before I flipped it over to nail it in.
The tophat hole was a good place to put the 5th clamp to hold things together. (two held on the 3-degree guide, two others held the horn to the guide.)

next I flipped it over to nail the bottom to the horn.
Then I checked to make sure everything is square while attaching the second side.
now that I have a good measurement, I can fabricate the front sheath braces and the back braces (half circles)

Next comes one of the parts that I have been fretting over the most: the front and rear sheath cleats. I'm just not sure how to get the radius correct on those little parts. This is where I'd love to have a CNC (or a friend with a CNC) mill.

I'm just not sure how to get the radius correct on those little parts.

Use the same method as you did to draw up the outline of the horn
Same piece of wood and pencil...

Grant Bunter wrote:

I'm just not sure how to get the radius correct on those little parts.

Use the same method as you did to draw up the outline of the horn
Same piece of wood and pencil...

Of course!

Thanks for pointing that out.

After looking at the sketchup, I can see that the backside angles on those sheath cleats are not critical.

To get familiar, I drew out the cleat locations on the bottom of my second cabinet: Now I can use the large diameter circle jig with my router to cut out 4 cleats at once (right/left/front/rear). I might even be able to leave the insides rounded as I cut the other 3 sets that I need. Then I can take the 4 eyebrow shaped pieces and cut across them.

I think I have a plan...

First on today's routing is to cut the radius into the front horn sheath braces. I built up a little jig to hold the braces while I cut the radius with the jasper jig on my router: Then I dry fit the braces into the cabinet: Now the big test, can I maneuver the driver between the radiused cuts: Yup, the driver fits!

Now, while I'm doing parts of about this radius, let's cut the back braces:
OK, now on to those pesky sheath cleats!

With Grant's help the other night, I finally came up with a strategy to build these little parts. I saw in another build thread someone did them with a pattern and a router table. But I didn't have a router table, and when Grant pointed out that one can get the 24" arcs the same way you lay out the bottom, a lightbulb went off. I switched the Jasper back to the Milescraft circle cutter, measured where the center point was relative to the arc on the bottom panel, and set up to cut the arcs. I left 1/4" of scrap between the left and right arc, and move the pivot of the guide half way across, making an eyebrow shaped piece:
After cutting the first eyebrow piece, I lined it up with the marks on the bottom of my second cabinet:
You can see that I have to cut out a 1/2" piece between the two cleats where the woofer baffle goes.

Next I cut off the wood below the lowest eyebrow in order to have a guide to place flat against the bar of my sliding table. Then I lined up the 4 eyebrow pieces, and nailed a bit of scrap to one side to hold everything together. The last cut was a bit tough, but the parts came out very nice. Here's a dry fit of the cleats in the horn: Next to dry fit the cleats in the cabinet:
My cleats are a bit different in size from the plans in that they have a radius along the inside, but this reduced scrap material. I'm ready to glue the cleats in, and cut the horn sheaths! Perhaps that will be a good time to bring cabinet number 2 along.

I made the side braces tonight. Setting up those 24 1/8" radius cuts was tough, especially the second one at the front. But they're done, as are the HF module backs (except for the dado)

And I cut my first throat filler blank. The router with the jasper jig worked surprisingly well. However my plan for cutting the bevel on the table saw did not. I need to find a bandsaw (as hifibob showed) or perhaps a hot-wire cutter.

billkatz wrote: I need to find a bandsaw (as hifibob showed) or perhaps a hot-wire cutter.

Make one. I sorta used this design http://www.instructables.com/id/Adjusta ... ith-Fence/

And a whole list of possibilities. https://www.google.ca/search?q=diy+foam ... UoAA&dpr=1

Tom Smit wrote:

billkatz wrote: I need to find a bandsaw (as hifibob showed) or perhaps a hot-wire cutter.

Make one. I sorta used this design http://www.instructables.com/id/Adjusta ... ith-Fence/

And a whole list of possibilities. https://www.google.ca/search?q=diy+foam ... UoAA&dpr=1

I thought about that for a bit, but for two speakers it seems like too much work. So I figured out a way to make plan "A" work. Plan "A" involves the box that will be the jig for cutting tweeters, turned on its side and my table saw.
While I wasn't able to spin the disk as I wanted, making 8 cuts to get it into an octagon, then 8 more made it round enough to spin it by the blade. Now they just need a bit of sanding. Here are the bevelled disks:
Now just a quick cut to remove the middle slice. My plan is to be ready to mount the woofer and test for interference this weekend.

Tonight was "learn how to use the dado blade" night. I made the 1/8" slots at the ends of the 3/4 sides, and the larger recess in the front side of the piezo module back. In the picture you can see the 4 sides, with a piece of 1/8" ply clamped onto one of them - nice and flush.

Now there are just a bunch of little parts I need for the modules: cleats and the little "L" shaped pieces at the top and bottom.

More progress tonight - I put one horn sheath on the first cab - I'm now ready to stuff in the pillow stuffing. Then I glued the horn assembly to the bottom of the second cab. I hope it will come along pretty quickly as I have all of the parts pre-cut from working on the first cab. The most progress was on the first melded array. I finished the piezo cutting jig from the panel jib plans. The biggest difference I had to deal with was that Bill appears to have a left-tilt table saw, while I own a right-tilt saw. This has the 45 degree cut coming from the opposite direction, away from the side rather than toward it. In order to keep the piezo still, I needed to add an additional stop to the jig. Here's the cut on one piezo:
I decided to go with opposite facing screw patterns, as I seemed to have not gotten the top/bottom cuts centered perfectly.

Next I built up the piezo gluing jig from the plans, and stacked up the cut tweeters. The whole set of 10 came up about 1/16" longer than nominal.
The plans state to do the initial tack together with airplane glue, but I don't have any. Another shopping trip. I do have the cans of glue that Leland sent that are specified for the second operation. I'm starting to feel that I can finish these things!

You don't need the airplane glue. Wipe the edges with the abs back to front so it does not get on the face with the brush that's in the can. Wipe most of the excess off the brush before you start.

LelandCrooks wrote:You don't need the airplane glue. Wipe the edges with the abs back to front so it does not get on the face with the brush that's in the can. Wipe most of the excess off the brush before you start.

Thanks, Leland - that seemed to work.

Tonight was what I called "3 glue Tuesday"

I cut apart an old pillow, stuffed the area around the horn throat, and hot-melt glued the first set of PVC pipes on. Then I got out the PL and attached the second horn sheath. Then I assembled the melded array. 3 joints, 3 different kinds of glue. This left me with two questions:

1) Do I have to trim (or sand) the hot melt glue at the PVC pipe/wood boundary? Or can I leave a little bump?

2) Does the tweeter array have to be without any holes at the glued joints? (I know it no longer seals the driver chamber, but for the tweeters to work well...)