How to NOT build DR200's with Compression Drivers

[kekani]

Not sure what the intent of this build thread is, but here it is, mistakes and all! Maybe the intent is for others to learn from me, instead of themselves? Whatever the case is, here is how I would suggest to NOT build DR200's.

First off, I read the plans. Many times. Still missed stuff.

Secondly, I expected less out of the build. Mistake - there's a reason Bill call this the most difficult build. And I increased that degree by using 3/8" instead of 1/2", and doing the compression drivers (the melded array is much easier).

I hope there's some value for some in preventing the mistakes that I've made.

Third, and this is the end game statement for someone like me, "The plans are designed with minimal tools." I have tools, so there's a number of process changes that suites me, sometimes for the better, sometimes not. I don't like drilling screwing gluing unscrewing filling as a process, because I'm lazy. There, said it.

At this point in the build, I can confidently say if you follow the plans, exactly, and view (not just review) sketchup along the way, you're headed towards better success than I.

Without going into details on the wood milling, let's start by saying I used what I have, in this case a table saw fence.
I used the offcuts from the throat horn support to provide the angles.
I should've used the throat divider for this
BTW - the angles are starting to give me a headache.


As Harley has called them, my "nappy" clamps make another appearance.
This is where the previous process shows some variation in the angle. PL to the fill.
Think Mortise and Tenon tablesaw jig, and you'll get how I clamped the throat tops and cut the steep angle.
Keen eyes will notice the "W" clamp to keep it square, taped to prevent glue from sticking, which you'll see later.
More angles. . .


I used an offcut from some piece to provide the angle for the "jig" - sorry, forgot where it came from, but its at the proper angle. Don't throw any cutoff's away, and you'll have this.
The baffle is nailed to the throat. This is where the 3/8" has variation - the throat divider is proud 1/8" into the baffle.
Probably could've done a 1/4" spacer under the baffle.


Trying to make up for the lost 1/4" by using 1/2" and 1/4" glued together for the driver spacer.


Stole this from HifiBob's DR280 build, which was awesome! Also used pocket holes.
"Wait! Kreg doesn't make 3/8" pocket hole jigs, do they?" No, they don't, but practicing on scrap allows it to be good enough.
W clamps make an appearance again, and cut the hole for the top hat.
Notice there's no radius on the back end?

[kekani]

This is where the "lost" 1/4" from the throat horn supports and baffle surfaces, when gluing the sheath braces. BUT, nothing a little persuasion from a clamp can't take care of. Its a non-issue, really, TBH.
Throat horn fillers are in.


Sheath cleats. What a pain - damn 3/8" changes the dimensions a little.


Used the Kreg again, with lots of clamps. W clamp in use to keep it square.


Horn sheaths stapled in, with brace spacers and extra blocks for the top hat glued in.
More angles - I tapered the radiused block the wrong way at the ends - the part that the back halves are going to be glued to. Chisel and sander took it down.


More clamps for the CD module - flange connector being glued, waxed paper in place.

[kekani]

A few things going on here. Module faces in place guided by the Horn Diffuser Brackets (the center one being glued in), and the Module Sheath Cleats being glued. Yup, 3/4", and one extra, for a reason. probably should've nailed this in from the module face side, just for good measure.


If I didn't say it before, damn fricken angles. . . Miter saw in use to make most of the cuts.


Although it looks like a lot going on, it just the module sheath being glued in on one of them. The other one is waiting, and the compression horn is just on the side waiting. Yes, this is done at the end of the build in the instructions, I just had the miter saw out and got to work.
You can never have enough clamps.


No nacelles, just a forstener bit off the drill press. Plan was to use T-nuts inside the driver chamber, which works well, for the center two holes.
What the heck was I thinking on the end holes - I driilled right into the sheath cleats! Used a brass insert instead, exactly what I use for my mortise and tenon neck joints on `ukulele.
I went to every big box store near me, and some small ones - no PVC! So ABS it is.
Filled with stuffing before glueing, of course. Good thing I saw this in another post, I would've missed this because although its in the plans, its at the end. . .
Damn if I had to measure out the ID and OD for the port holes.
Damn if its not in the plans!


Of all the measurements I was concerned about , this was it. And it was the most uneventful. Pocket screw again.

[kekani]

There's a reason the High Frequency Driver Mounts are glued in AFTER the Horn Assembly is glued it - it won't fit if you glue it first. Did NOT make this mistake, thankfully.


Gluing in the end diffuser brackets.


May as well install the driver mounts. 1/4x20, T-nuts and Locktite blue.


Old School planing. No dust.


You know, I'm missing a picture of the back halves being glued. WTH?!! Anyway, it was a bitch! Had to taper the center, and cut it pretty much to size. Prebending for a week helped. I'd like to say its a tight fit, but that would be putting it nicely. It is TOO tight to fit, so bending, cracking, reglueing, filling with PL, etc etc etc. It did crack, in two places, but nothing staples and PL didn't fix. That stuff is good!

Because of the taper, I marked each side specifically for each side, and cut it close, glued, nailed, and added some weight.

[kekani]

Where the heck do I drill the hole for the wiring? Sketchup? Plans maybe?
I put it on the bottom section - hot melt to fill the holes.
handles routed out, back made out of 1/4".


BTW, because of the fit, the CD modules are side specific, and they are tight, which is why you can seal it per Bill, when I asked this question on SimonD's thread. Since its ported, and will remain as such, I'm thinking non-issue to seal the CD module.
Also, I installed the feet with T-nuts before the back went on.
Also went ahead and filled the driver chamber with foam.


Straight pattern routed everything, corner rounded, D/A orbital sanded (80 grit - used to use 100, 80 is good), and layed some finish on the bottoms.
I did NOT notice that the side braces were not well glued, so more PL, and clamp persuasion.
Should've used clamps and straps to do this instead


And that's all you get from me for now. I'll be working on the crossovers and finish - I'm just going to Duratex everything - roll everywhere I can, and spray the compression modules. We'll see how that works.

Still contemplating recessing the top hat and Speakon plate. Getting lazy, want it to be done so I can focus on instruments again. . . besides, they're not for sale, and ONLY for me!

[Tom Smit]

Ain't it fun!?

BTW, because of the fit, the CD modules are side specific, and they are tight, which is why you can seal it per Bill, when I asked this question on SimonD's thread. Since its ported, and will remain as such, I'm thinking non-issue to seal the CD module.

I built a proto-type-for-me TLAH with bad joints (good ones will be coming in the future). At 2 volts it squacks through the openings. I only listen to it at 1.5 volts which is plenty loud in my shed.

[SimonD]

Hi Kekani

Do you have any more detail on your nacelle alternative? I can't see where you used the brass inserts, are they the dowel type with a threaded hole through the side?

Cheers S

[kekani]

Hi Kekani

Do you have any more detail on your nacelle alternative? I can't see where you used the brass inserts, are they the dowel type with a threaded hole through the side?

Cheers S

1/4-20 threaded brass inserts. Shucks, I JUST installed the 4 that were missing. These only went through the holes against the tops and bottoms. The middle holes I just used T-nuts on the inside of the driver chamber. I couldn't use T-nuts on the tops and bottoms because of the cleats. Of course, the cleats are what allows me to use the inserts.

Here's another image from another project. I used a step drill to open up the top of the hole so the insert goes straight in, and doesn't crack the wood. Not necessary for the plywood. Well, actually, I cracked one section of the sheath brace when installing the insert, but it'll be sealed anyway - another non-issue for me.


For the record, I was concerned whether I'd be able to pull this off. Bill had mentioned that using a Forstner Bit this way would apply to guys with large enough drill presses, which is why its not in the plans. I have a single Kreg jig that I thought I'd use if it didn't fit under my drill press. Fortunately, it did. I have a little 9" drill press (I think that's what it is - the smallest one at Sears). My issue is I wanted it to be removable, and not with wood screws, hence my use of Tnuts and inserts, with Allen Head cap screws.

[SimonD]

Thanks Kekani, I presume the front access holes are just tubes down to the base frame?

[LelandCrooks]

Nice

[byacey]

I would recess the the speaker jack cups and any handles; this prevents the hardware from scratching up other gear when packed for transport.

I made inside router templates the shape of the cups allowing the use of a follower bearing - router bit. I cut the recess about 3/16 of an inch deep; that in conjunction with countersinking the holes on the plate ensures that flat head screws seat down flush with the plate or handle sheet metal surface.

[Grant Bunter]

So, resistance was futile!

I enjoy your different approach in your builds...

[kekani]

Ain't it fun!?

There were certainly more than a few points in time where I asked myself, out loud:
"Are you kidding me?"
"What the hell did I get myself into?"
"This can't be right?"
And many, many more, with expletives of course.

Thanks Kekani, I presume the front access holes are just tubes down to the base frame?

It's a 5/16" hole (for the 1/4" cap screw) inside a 7/16" tube. No, it doesn't go down to the base frame. Here's a pic of a 1.5" cap screw inside, and one on the outside so you can see how deep it goes in.
Note: this is for the center 4 screws; the ones next to the top and bottom are only 1", as the insert isn't as deep as the Tnuts.

I would recess the the speaker jack cups and any handles; this prevents the hardware from scratching up other gear when packed for transport.

I made inside router templates the shape of the cups allowing the use of a follower bearing - router bit. I cut the recess about 3/16 of an inch deep; that in conjunction with countersinking the holes on the plate ensures that flat head screws seat down flush with the plate or handle sheet metal surface.

Very good point about scratching up other gear. However, I can't rightly recess 3/16" into the 1/4" back. Well I guess I could and add in some block on the backside to screw into, but, too lazy.

Also too lazy to make a template, which I would've done a while ago if I had known I'd be building more than one cab.
So, I took advantage of the Duratex, and scribed the outside of the jack plate, and free hand routed.
You can also see the depth being set, exactly the same thickness as the jack plate.
BTW, do you know the secret to free routing? If you do, let me know
Note: Not going to recess the adjustable top hat - it is just too close to the baffle to make it worth it.


Leland and Grant, thanks for your always supportive comments. This was a real PITA build. I can't say it was enjoyable, BUT, the design and detail that Bill put into this is very neat, to put it simply. Honestly, each time I see someone starting an OT12 build I always thought to myself "Why not just do a pair of DR's and be done with it?"
Consider me humbled.

Still need to work on the crossovers - maybe tomorrow, and do more finishing. Damn if I didn't forget to order corner protectors. . .
I'm liking the look of these, even at this stage. Listening with my eyes I guess.

[SimonD]

Thanks Kekani
Thats perfect, I really appreciate you taking the time to show me the details.

With regards pulling your hair out and driving yourself mad, I decided very early on in the build that I wouldn't question the plans . My mantra was "If it didn't look right then I didn't understand it".
I suppose that most of us who take on such a project have a fair bit of technical know-how, and that drives us to always question. History also tells us that most plans DO have errors in them and the madness comes when we can't decide if the plans are wrong or we don't get it One important tool that I put in the workshop is.... a chair..... I'm begining to think my brains are in my feet because as sooon as I sit down and read the plans again, things seem to come clearer (if that doesn't seem to be working then It's probably time for a glass of wine as well )

Fantastic work so far, let's see if I can catch up to you this week? I ordered the Duratex today, last part of the puzzle

[kekani]

Thanks Kekani
Thats perfect, I really appreciate you taking the time to show me the details.

With regards pulling your hair out and driving yourself mad, I decided very early on in the build that I wouldn't question the plans . My mantra was "If it didn't look right then I didn't understand it".
I suppose that most of us who take on such a project have a fair bit of technical know-how, and that drives us to always question. History also tells us that most plans DO have errors in them and the madness comes when we can't decide if the plans are wrong or we don't get it One important tool that I put in the workshop is.... a chair..... I'm begining to think my brains are in my feet because as sooon as I sit down and read the plans again, things seem to come clearer (if that doesn't seem to be working then It's probably time for a glass of wine as well )

Fantastic work so far, let's see if I can catch up to you this week? I ordered the Duratex today, last part of the puzzle

Truth be told, besides Grant, Bob & a few others, your build is right up there for me, so I was paying attention. Especially since you're doing the compression drivers. Now you know why I had those questions on your build.

Because I've been through a few builds real time, I thought I'd just post this when I was done (okay, almost done), so if anyone wanted to glean through how 'not' to do it, they could do it in one or two pages. And with this one I thought I'd poke a little fun at myself at the same time.