Diving in - a pair of DR250s

[billkatz]

With my Titans ready for some internal paint, I decided to start on the DR250s. I had about 3/4 of a 4x8 sheet of BB left, so I played around with cutlist and found I could make all of the horn and baffle pieces, as well as one set of top and bottom panels. Next I need to get down to the plywood store and pick up another sheet of 4x8 1/2" as well as a sheet of 1/8".

I reviewed the very good build threads that Grant, bman, and hifibob did on their DRs, and motivated by a picture from bman my first DR jig is similar to his tenon jig to cut the 57 degree angles. I had to make some changes as his table saw appears to be a left tilt, while mine is a right tilt. And with my sliding table to the left of the blade, my fence is right at the blade.

I also cut out the two throat horn dividers - they were easy with no compound angles.

Next I will build a jig for doing the compound cuts on the throat horn sides. I can see where a compound miter saw would really come in handy here. But that's not in the budget, so I'll have to work out a jig for the table saw. Then I'll need a jig for routing the inner rectangles in the throat horn supports. I'm impressed by the jigs that hifibob built, but they seem like overkill for just making a pair of speakers.

Dumb move of the day: starting to crank the blade over to 33 degrees without changing the zero clearance insert out for the dado one. That put a little dent in the saw blade, so I stopped by home depot to pick up another. I'm hoping that sending it out to a good sharpening shop will get all of the teeth back in line.

[Grant Bunter]

Thanks for the kudos mate

For another DR250 build thread for more inspiration and a different idea if you're going to do a full back, check out ncgrove's thread as well;
http://billfitzmaurice.info/forum/viewt ... 30&t=20296
It's another based on latest plans.

Then there's ripndeb's and Tedwards DR250 builds on page 3 of the build threads as well, though they are older style...

Drey Chennells DR250 Stealth grill ( http://billfitzmaurice.info/forum/viewt ... 26&t=18416 )
and porting mod can be seen on page 8 of my build thread as well...

[Hackomatic]

Bill's eat up!
True addict . . start another before finishing the first . . . Right there with ya, bro.!

[billkatz]

Thanks for the pointers to other threads, Grant - I perused them all.

I finally got some time to work on the horn pieces today. I made a jig very similar to bman's, except I slid mine against the fence to the right of the blade. I did make a minor error cutting these bevels at 13 degrees instead of 11 (I didn't change the blade after beveling the bottom edge) but that error seems small enough that PL will take care of it. (2 degrees across half an inch is just over 1/64th). Now I'm thinking about good ways to make the large rectangular holes in the throat horn supports.

First I made the angle cut along the long side of the throat sides:

Next I made the first compound cut:

The brad nailer really made assembling the jig easy, once I got the angle right.

My picture of the second compound cut didn't come out.
The second bevel was against the fence.

I also beveled the throat horn supports, and then set all of the pieces together:

Once I cut the rectangular holes, I can glue and brad everything together.

Any advice on the large rectangular holes? I figure if I can get one just right I can use my pattern bit in the router to copy it. Perhaps a rising table saw cut for the long sides and some jig saw work.

[Grant Bunter]

Any advice on the large rectangular holes? I figure if I can get one just right I can use my pattern bit in the router to copy it. Perhaps a rising table saw cut for the long sides and some jig saw work.

Honestly, you would need to make a template and cut the rectangles off that.
Worthwhile perhaps if you intend to make more cabs, but in the similar amount of time to making a template, you could have marked up all 4 rectangles, drilled 4 x 1/2" holes in each corner, and cut them out with a jigsaw.

Also, because of the shape of the rear of the horn, you can't put both horns face to face meaning you could cut two rectangles at a time.

Just right? No one will ever see them, except for the pics you may post up here on the forum...

edit: nice work so far

[billkatz]

I took Grant's advice that the holes don't need to be perfect, and set about cutting them. I drilled 4 corner holes, and cut the long sides of the first one with a plunge cut on my 18V circular saw. It was OK, but not as straight as I wanted. I cut the long sides of the next one with a rising table saw cut. This worked very well, and I used it for the remaining cuts. With a calibrated fence the cuts went quickly.

Then I finished the cuts at each end with my jig saw, cutting the ends of the long cuts and the short cuts. You can see the cuts are not perfect as they meet the holes, but I hope this is good enough for these inside holes.

Next I glued the horn sides to the horn supports. I tried drilling a jig as in the plans, and it seemed like more work than needed. I reverted to using a jig, but with a clamp, and then clamping the side with 4 other clamps - just long enough to shoot some brads along the seam. While the brad gun made some things on the titans easier, this is where it really shines! I had things clamped up, shot the brads, and was immediately able to take the clamps off and use them on the next assembly.

Now I have 4 pairs of horn sides and horn supports glued up and drying:

I'll give them a couple hours, trim the PL, and let them set overnight. Perhaps Friday I'll finish these assemblies, and start work on the baffles.

What diameter do the holes in the woofer spacer have to be? I haven't ordered my speakers yet. To Neo or not to Neo - that is the question...

[escapemcp]

What diameter do the holes in the woofer spacer have to be? I haven't ordered my speakers yet. To Neo or not to Neo - that is the question...

Who's going to say it! Ok... I'll do it:

Don't make the driver holes until you have the driver in hand. Not worth the risk of messing it up.

I can see you are motoring and want to get on with it, but don't create extra work (and wasted wood)!

What would you say your level of woodworking is Bill? I can see that that rectangular hole is a little wobbly and I'm hoping that you are at best average skilled. This is NOT because I want to bring you down or anything, but I would think I am somewhere around that skill level. If you are at that level and can pull off the DRs, then I think you are going to inspire me to make mine by showing me that it is possible. So if you are at that level - THANK YOU. There's far too many perfect DR builds from the likes of Nim, Leland, Harley, HFBob et al. (showoffs! ), I'd like to see one that is not quite as immaculate and more a representation of what I'd be likely to achieve.

I hope this all makes sense... I have re-written this about 5 times, as it sounded initially like I was ripping on your skills... I am definitely not.

[billkatz]

What diameter do the holes in the woofer spacer have to be? I haven't ordered my speakers yet. To Neo or not to Neo - that is the question...

Who's going to say it! Ok... I'll do it:

Don't make the driver holes until you have the driver in hand. Not worth the risk of messing it up.

I can see you are motoring and want to get on with it, but don't create extra work (and wasted wood)!

Yes - I know that's the standard answer, but there are some who have done this enough that they know the answer. At some point I'll just have to send off my order to Leland for a pair of DR250 kits...

What would you say your level of woodworking is Bill? I can see that that rectangular hole is a little wobbly and I'm hoping that you are at best average skilled. This is NOT because I want to bring you down or anything, but I would think I am somewhere around that skill level. If you are at that level and can pull off the DRs, then I think you are going to inspire me to make mine by showing me that it is possible. So if you are at that level - THANK YOU. There's far too many perfect DR builds from the likes of Nim, Leland, Harley, HFBob et al. (showoffs! ), I'd like to see one that is not quite as immaculate and more a representation of what I'd be likely to achieve.

I hope this all makes sense... I have re-written this about 5 times, as it sounded initially like I was ripping on your skills... I am definitely not.

I'll freely admit my skill level is not up to Leland's or hifibob's... I'm probably average, but I have put some effort into obtaining the tools I need and learning how to use them.

In this particular case it was a calculated decision of "How pretty/perfect do I need to make this hole?" If it was going to show on the outside, I would have used the same methods to make a rough hole 1/8" smaller in all dimensions, and then lined up guides and used the router pattern bit to make the lines perfect - perhaps building a template and then using it to finish the other four. But as Grant pointed out - these are deep inside and will never be seen again, so a 32nd or two of wander getting into the corner holes shouldn't affect anything.

[Mark Coward]

To Neo or not to Neo - that is the question...

Neo is the One

[billkatz]

To Neo or not to Neo - that is the question...

Neo is the One

Thank you - I got the same message from Bill when he said it was worth 5dB. Cheaper than a second set of cabs.

I made some progress this weekend. I squared up the horns, and tacked in the center support:

Then I put the remaining ends on, and cut the angles at the top and bottom of the assembly after the glue set up.

Then I started working on a pattern/jig for the two 4" square holes at the top and bottom of each baffle. Since there were 8 identical cutouts to be made, and I can see the the audience here likes things tidy I decided to make a pattern so that I can rough out the cuts in the baffle and then make them pretty with my router. What's the point of investing in a nice router if I don't use it?

I made more progress today as I stopped off at the plywood store and picked up another 1/2" sheet which should be enough to finish the cabs. They didn't have 1/8" Russian Birch, so I went for the backup Italian Poplar for the 3 ply, 1/8" material. I made the first cuts in that sheet so I could get the pieces down to a size where I could lay them flat so that they didn't curve prematurely. I was careful to lay everything out with the correct bend direction. (my supplier actually has both 4x8 and 8x4 sheets so you can choose your bend direction relative to the sheet dimensions)

Now I have to finish those baffles and lay out the top and bottom.

And this point I can appreciate the simplicity of OT12s. The amount of work I put into the 4 horn sides and the baffle would just about finish an OT, while the DR has a bunch of work. But with the 1/8" material in hand, it definitely feels doable.

I'm thinking about short sides with the rounded backs showing, but I'm now wondering if the poplar is too soft for that.

[escapemcp]

You could put several layers of the poplar (I think).. it wouldn't stop it being soft, but it would mean it could take a few dinks and you could just bondo and duratex over the top for a clean looking repair.

I totally understand your reasoning about the slightly off rectangular hole cutouts. When I was building I followed a certain member's sig:

Accept the fact that airtight and well-braced are more important than pretty on the inside.

and it served me very well. My cabs can get messy as hell inside, but they don't leak and they look good from the outside - job done I even had a comment that I never built the cabs and instead I bought them and he said that I was just blagging it... he was trying to have a go, but he inadvertently gave me the best praise that he possibly could have done He never saw the insides or he would have never of made that comment!

Watching this thread with great interest. Nice to hear the Otop comparison to where you have got to so far. Would that include all the Otop 'faffing about' with the crossovers, arrays and such, or just the woodworking stage? Thx

[Grant Bunter]

this point I can appreciate the simplicity of OT12s. The amount of work I put into the 4 horn sides and the baffle would just about finish an OT, while the DR has a bunch of work.

You're quite right. Not said in any way to put you or anyone else off building DR's, but really, you've just begun.
For me, having the top and bottom on seemed like a major step forward.
The cab seemed to get quite solid when I put in the reflectors, so that seemed another major step forward.
Then, because you have to have completed the horn, horn sheath and module in order to do so, putting the sides on seemed to be the next major step forward.
And so on it goes.
The results are worth it

You could put several layers of the poplar (I think).. it wouldn't stop it being soft, but it would mean it could take a few dinks and you could just bondo and duratex over the top for a clean looking repair.

The 1/8" sheet is for horn sheath and horn parts and outside of the module. No need to stick any layers together. Most of that (except the rounded backs) is inside the cab, so, unless something extraordinary happens, in the dink free zone.

I'm thinking about short sides with the rounded backs showing, but I'm now wondering if the poplar is too soft for that.

If it were my cabs, I'd be inclined to think the poplar is to soft to be left exposed. That's just me though.

In your other thread (Beta10 Vs 2510) you asked about overall weight.
As you are probably aware, I did the full back and used the beta10a (I honestly didn't realise at the time of building that the difference would be 5dB between the two drivers).
My cabs are just large enough to be a little ungainly weight wise when trying to lift them onto a stand set at the correct height, though I have developed a technique to achieve it without issue. I'm about 5'9" and about 210lbs.
So if you save a few pounds with the 2510, and also by using 1/8" poplar, that would make handling the cabs a little more manageable...

[Harley]

rect_holes_cut.jpg

I wait until I attach these to the horn before cutting the slot - a lot easier to manage using the table saw as a plunge saw or using a jig saw. Slotting those narrow pieces invites danger IMO.

Whoops - slotted bits didn't show - refer billkatz's second photo upstairs a bit.

[LelandCrooks]

Get some wood hardener for the poplar, give it a coat. Duratex will still stick, the face will be hard as a rock.

[billkatz]

Good suggestion on the wood hardener - I'll have to look into that.

I finished the baffles, using a template and router for the 4 larger openings on each, and a circular saw and jigsaw, and being very careful for the central opening. I used some scrap pieces to alight the horn front and the baffle - thee 3 degree cuts lining up perfectly.

Here is the horn all clamped up:

Both horns are finished, save for the woofer spacers, which I can't complete until I order the woofers. Next task - lay out the design on the top and bottom of the cabinets, and fabricate the horn sheath braces. I can see how getting the horn sheaths on will really be a huge step toward making it look like a speaker cabinet!