BillFitzmaurice.info

(Cont.) I found this polyester foam batting at a local Joanne's Fabric store. It's an alternative to the regular high density foam and is more fire retardant. It's 1 inch thick. For right now, I just measured, cut and fitted all the panels in the driver chamber. I've got some Acouta-Stuf that I'll use in the throat compartment area. I'm doing it now, where it's easier to get to, but did not install it. I'll hot glue mount it toward the end of the build. Now, it's time to start on the Melded Tweeter Array section. The back of the module is a flat panel. BTW, it was these panels that I was rough cutting, when I had my incident yesterday. For some reason, it was a PIA to do. Even with paying attention to detail, I still confused the angles and cut one piece wrong, TWICE! Of course, going back and forth to watch the football games probably had something to do with it. I've got to get a TV in my shop. (For the sake of pride, I did NOT take pictures of those mistakes.)

(Cont.) Because I'm building the MTA version, there's a clearance groove for the tweeters so that they can fit. I used my dado blades, set at 1/4" x 3-1/4" wide (the plans say 3", I added extra just to be sure). Dry fitted. Now even though I have been as thorough as I can to keep everything square, it's easy for small increments of off-measurements to creep up on you and cause big headaches later. The plans allow and are forgiving of this "slop". But what I like to do from time to time is measure the actual layout, draw them down on the parts, and make those corrections at small increments as well to keep the big headache "gotcha" from occurring.

So here, I've drawn the centerline of the cab, using a drafter's triangle and the reference lines drawn from earlier to help and maintain the alignment of the HF module that is about to be built. Drafter's triangle removed. (I also brought out the MTA, built earlier and verified that everything would fit, and that the angles all matched.)

(Cont.) The HF module is built, but not glued to the main cab. But it's required to build it in the cab. So I went an extra precautionary step and taped and wax papered the sections to prevent the HF module from bonding to the main cab. You can't see the wax paper in the photo very well. It's taped along the long side edges of the driver chamber and the top and bottom areas. Next was to put the back panel back on the main cab and temporarily screw it to the front driver chamber braces. Next, was to fit the front HF module vertical braces and temporarily screw them in from the top and bottom. This was as far as I got. My 49ers game was coming on TV, so that was a good stopping point. Tomorrow will be the small cross braces, and perhaps the sheaths to finish up the HF Module.

(BTW - my 49er's kicked the Texan's ass! 34-3, Sorry Texan's fans )

Bman,
Thanks for your interest
You can have a look here:
http://billfitzmaurice.info/forum/viewt ... 30&t=18214

Your thread is sooo reminding of my own build in many ways, though I cut the trench for the melded arrays with my router.

edit:
I can't see pillow stuffing in the throat horn area (p41). It occurred to me during my build it was easiest to do that before attaching the horn sheaths. Bit late now, but don't forget...

Bman wrote:(BTW - my 49er's kicked the Texan's ass! 34-3, Sorry Texan's fans )

Yeah it wasn't to pretty at all.

I'm really loving all the pics, BMan! Thanks very much for them. The groove you dadoed out of that front panel; is that for clearance for rear of the tweeter array? The strips of batting you cut out turned out well. They fit great.

I tried to do the same thing for my OTops, but b/c I didn't install the crossovers in precisely the same locations in all 4 cabs, precutting most of the strips wasn't possible; I had to trim/fit each one by hand. That was my least-favorite part of the whole build.

Your DR build is looking fabulous. Keep them pics coming!

Wow Bman.. Your build looks phenomenal! You got some skills for sure! Im dying to build these little baby DR's myself for my DJ booth.. Please let us know how you like them.. Keep the great pics coming.

Well, as expected, that 4-letter word (work) took some time away from the build. It's amazing how you can loose your build "groove" after a few days off of it. Anyway, got back to it. Getting to the home stretch.

Grant - Thanks for the link. It was very interesting to read it. You're right, kinda of de ja vu. But from my point of view, in reverse. I do plan to stuff the throat area once everything is done. I got some extra Acousta-stuff laying around, so I'm going to use that.

miked - Yeah, the groove is for the array clearance. I did a little dry fitting and it NEEDS it.

hifibob - Thanks! I hope this build helps you with yours. It's intimidating at first, but if you read the plans (till you can recite it from memory - well not quite that well) and plan carefully, it's not too bad. But I'm learning - PATIENCE and diligence will go a loooong way.

Anyway, on to it...

Thought I'd gross ya' out first. Since it's approaching Halloween, somewhat appropriate. The eventual result of the throwback incident. It took a couple of days before this ugly thing showed it's head. You can definitely tell the long side of the board got the best of me and my left thigh. Like my GF reminded me, I was lucky - had it been just a couple more inches to the right.... well you get the idea. I finally got my adjustable tops. I wanted to set them flush, so I made another routing template out of scrap and used the outline of the top. I cut it out with my jigsaw as close to the outline as possible, then smoothed it out with a drum sander attachment on my drill press. Perfect fit! I drew an outline on the bottom of the cab to help with placement of the template. I wish I had the actual top when I was first cutting out the hole for it. I didn't have it at the time and just used the measurement in the plans. It was a bit to large for my liking. As you can see, the mounting holes are really close to the edge. Adjusting the depth of the router bit accounting for the thickness of the template and flange of the top. I used my smaller 1hp trim router to do the job. I have an auxiliary clear base made out of plexiglass so I can see what I'm routing.

(Cont.)

Routing template attached with double-sided carpet tape. After routing. As you saw in the picture when I set the depth of the router bit, you can see that the flange of the top is almost half the thickness of the BB. I routed the inset depth a hair below the surface because I'm going to seal it off with speaker gasket tape. That should set it back to flush once the top is installed. I also am using a flush bolt, fender washer, washer, and nylon insert lock nut to secure the tops to the cab. This way, the strength of the flange will couple with the panel to offset any weakness caused by thinness of the BB after routing the inset. Dry fit testing of the top hat. Now on to finishing the HF section. These are the top and bottom module faces for the melded array. Here, the faces are glued in. The faces are also profiled so the array can fit when installed. I first used a straight router bit in my router table, using the fence and a stop to guide me. Then used a stationary belt sander to smooth out the gentle slope.

Bman,
pretty sure the idea is to fill the are, hence "lightly stuff with pillow filler"
You're acousti stuff looks a bit to much like a pad to do that.
New pillow = a couple of bucks.
I used about half one for my pair of DR250's, so I have about half one left for another pair...

(Cont.)

Here with all the small cleats installed. Front view. Side view of the cleats. I pretty much used the same technique for making these as I did for the ones in the driver chamber, only on a even smaller scale. Grant, I don't know how you did it, but this was definitely an exercise in frustration and doing it over and over a few times before I got it right. Luckily, they are small enough that there was enough scraps to allow for this. Notice how the middle cleats had to be cut as thin as the front vertical faces, but the bottom and top ones were left at full size. That's because, the top and bottom will clear the array, but the middle ones won't unless you trim ("skinny")them down. I'm thinking of possibly fitting the components of the HF filter inside the module (if they will fit). What do you guys think? They will probably have to layout more inline with each other. The best part of being interrupted by real life work, is that I was able to snatch a couple of nice bonuses... real nice ones. So I was able to procure some more toys.
1. Ordered 2 Lab 12c's for my Tuba 45 build.
2. GX3 for the tops and GX7 for the subs.
3. Driverack PA+

This is really looking to be a kick-ass party rig! See, I'm paying attention to the advice of this forum.

Of course most of it went to get my youngest her car, but I still got my toys... can't complain.

Grant, the pad that you saw in the pics isn't Acousta-stuff. I actually found it when I was looking for foam in a fabric store. It's a fire safe alternative to the foam, but with all the same properties. Acousta-stuff is actually like pillow stuff. But it's fibers are more controlled and consistent designed specifically for speaker construction. I happen to have a couple of extra pounds left over from a speaker project last year.

Bman wrote:Grant, the pad that you saw in the pics isn't Acousta-stuff. I actually found it when I was looking for foam in a fabric store. It's a fire safe alternative to the foam, but with all the same properties. Acousta-stuff is actually like pillow stuff. But it's fibers are more controlled and consistent designed specifically for speaker construction. I happen to have a couple of extra pounds left over from a speaker project last year.

Cool, it's all good then

Grant, I don't know how you did it, but this was definitely an exercise in frustration and doing it over and over a few times before I got it right. Luckily, they are small enough that there was enough scraps to allow for this. Notice how the middle cleats had to be cut as thin as the front vertical faces, but the bottom and top ones were left at full size. That's because, the top and bottom will clear the array, but the middle ones won't unless you trim ("skinny")them down.

I traced the dimensions and angles etc on wax paper before attaching the backing plate and cut them with a jigsaw. Close enough fit. Still messed a couple up though.

For the middle one, I didn't trim down the whole cleat. I just cut a chamfer at the leading edge where the array goes in, trimming until clearance was achieved.
I find it easier to angle the array in one side first, then the other side, rather than try and put the array straight in so to speak.

I'm thinking of possibly fitting the components of the HF filter inside the module (if they will fit).

I also though of that, until I considered that the only time I wanted to take the array out of the module was if a piezo died. Hopefully never!

You can see how I did my passives.
2 halves, one LF, one HF, mounted on 1/4 ply, either side of the adjustable top hat. The boards screw to the cleat on the outer edge of the driver chamber on the outer edge, and on the inner edge, to the strip of 1/2" ply I laid down either side of where the top hat sits so the screws for that have extra meat to bite into.

Those two extra strips are highly recommended, especially since you routed some material out...

I had a hell of a time getting the melded array in the HF module on the DR250. I spent hours with a hammer and chisel and a dremmel tool trimming down the HF sheath braces until I got the array to fit. I ended up cutting out the middle joining pieces because they were getting to be wafer thin by the time the array fit. I must have cut the piezos a bit too fat.

ncgrove wrote:I had a hell of a time getting the melded array in the HF module on the DR250. I spent hours with a hammer and chisel and a dremmel tool trimming down the HF sheath braces until I got the array to fit. I ended up cutting out the middle joining pieces because they were getting to be wafer thin by the time the array fit. I must have cut the piezos a bit too fat.

If you cut the piezos 3/32 inch too large that translates to 3/16 inch when you glue them together, and that's about 1/8 inch too wide to easily fit in place.