8 x DR250 build

[CoronaOperator]

Hello everyone, Summer is over so I'm back in the shop again! This time I'm building 8 x DR 250's . Why 8? Well, I need 4 (2 a side) for our main room, 2 more for delay stacks/daytime radio further down the venue (it is about 120 feet long with only 10.5' ceilings) and the other 2 I'm not too sure. I know once you set up your cut on the table saw it only takes a minute to run more wood through it so that's one reason. Some times we do a 2 room show so they could be used there and I'm sure the DJ's would love to use them as monitors as well although I'm not too sure they would work all that well as close range (~5') monitors with the narrow vertical dispersion. As long as we don't have a tall DJ and a short one back to back they might be alright.

Well those first throat horn sides sure make you realize that you need to get your woodworking skills up to speed. Just trying to make sense of which way the bevel cut goes sure gets your sketchup skills in order as well. If all else fails PL will save the day.

So after the throat horn sides were cut I came up with a pretty good system for quickly making a jig for all the cuts on the tablesaw sled:

I used a scrap piece of chloroplast laid down to let me know where the saw cut line was as with all the bevel cuts, the cut line wasn't obvious. Then I lined up my cut and using the brad nailer, I nailed down a piece of scrap (1 in the photo) with a couple 1" brads right into the MDF sled. Then going a bit wide I made a test cut and kept on inching my way to the blade until the pencil line lined up. Then I nailed another piece of scrap (2 in photo) to lock in that position. After that I just ran all my other pieces through without measuring or marking the cut lines, just blind faith.


Same system for the other cut on the other side. You can see where I keep the blanks on the left side of the table, run them through, then place them on the right side of the table when done. Wash, rinse and repeat and 8 cuts done in less than a minute. Afterwards, I lift up on the chloroplast and the scrap pieces nailed into the MDF sled top just pop right out.

Loving the nail to the sled idea, I made a pattern using scrap to cut the slots in the throat horn supports:

With the brad nailer it only took a couple minutes to put together.


Test fitting the blanks. The small gap is from the bevel on that side, if there was play the cut would come out sloppy.




All the throat horn pieces ready for assembly.

[CoronaOperator]

During the throat horn assembly I ran into a problem right away:

I cut the throat horn sides too small: .

So I glued a couple of these to my new found work table/miter sled with hot melt glue:


Then with the pieces all clamped as they should be I used shims to raise the height of the horn sides until flush with the dividers:


Then I used hot melt glue to lock it in place. The 1/8" gap allowed for the glue to completely flow into the gap. I tilted the table a bit so gravity could help me a bit:


Once the glue was hardened but still a bit warm, I used a utility knife to cut the edge smooth:


Success!! As an added bonus, the hot melt glue dried in a few minutes so I could go on to the next step without having to wait overnight for the PL to dry!

[CoronaOperator]

Next was gluing up the throat horns:

I nailed in place a couple scraps on either side to keep the overall width the right dimension and a bottom piece to keep everything square. I also used a speed square to keep the dividers vertical.

A nice shot of the horns coming together:


Laying out the driver hole: I used diagonals to find the center and then worked from there:


Again another jig made from scrap nailed to my miter sled :


Test fitting the blank with a hole drilled for the pattern following router bit to fit through:


After the cut:


Then using a jigsaw, I squared off the round corners:

[CoronaOperator]

Again, I nailed scrap to make a jig to the miter sled to make the "feet":


Test fitting the blank:


After cut:


Making 8 DR's, the patterns really helped to speed thing up. Next up was gluing the two pieces together. I made a little assembly jig to keep everything square and the top level. I forgot to take a picture of that. Here is all the assembly's posing for a picture:
.

That was the end of day 3 in the shop and the end of the first week.

[LelandCrooks]

Pretty close to some of my DR assembly jigs. Nice.

[CoronaOperator]

Week 2:

I rough cut the foam throat fillers into squares. Then I made a hardboard circle template cut with the jasper jig on the router. If you look to the right of the foam/hardboard sandwich you can see a pin that I placed in a hole drilled into my miter sled. I placed the sandwich on the pin and cut a slice with the table saw, rotated the piece a bit, then made another cut, etc. Eventually it gets round. I cut another smaller hardboard disk for the top shape, placed it on top, then used a random orbital sander with 60 grit to sand the discus shape to size. Messy, took some time but I managed to get all 8 done to size.

I laid out all the top and bottom lines and cut out the "butt cheeks". All 16 of them, whew!


I cut out the driver blanks, then with just 2 scrap pieces nailed to the miter sled, I was able to do all 4 sides! 32 Cuts in all in only a couple minutes. Just cut, rotate, cut, rotate ....


The driver finally arrived so I was able to cut out the driver holes. Oh ya, I'm using the deltalite 2510. I would have loved to try the 3010MB but that premium x 8 was too much $$$ that I could use to make more subs with and I don't think I'll need the extra output. This time I put a piece of scrap down as not to destroy the miter sled too much, lol:


Then just some assembly and that's as far as I got so far.

Final picture of the babies growing at the end of yesterday:

[Scott Brochu]

Great start!

[CoronaOperator]

Pretty close to some of my DR assembly jigs. Nice.

I hope that means I'm on the right track. I however scrapped mine right after the cuts. I don't think I'll have any use for them after this build .

Great start!

Thanks Scott, I'll need all the encouragement I can get, I think it's going to be many a long day in the shop.

[CoronaOperator]

Today it was time to test fit the driver and test for rub:


My shop is in the basement and the DJ booth is upstairs and down the hall. 30 Hz test tone at 8 volts .... and it rubbed. Back down the hall, down the stairs, take the driver off, sand a little, driver back on, up the stairs I go ... and it rubbed some more ! 3rd time was a charm so I had one box complete. 7 boxes left ... most of them rubbed ... some more than once . I only have the one driver for now and it looks 20 years old already putting it on and off 20 times. That and I think I went up and down those stairs 20 times today carrying those boxes! That was my workout for the day!

After that I spotted a problem on 4 of the 8 boxes:


My center divider ended up a little crooked on half the boxes . Luckily I read some of the other build threads on here and someone else used a multitool to fix the same problem. I had just bought one on sale for $30 last month and hadn't used it yet. These things are great!


They can un-PL anything you PL'd without making a mess!

On the right is AFTER the cut! No sanding or anything!


The finished repair. I spent more time worrying about it than fixing it. It didn't take very long at all.

The last thing I did today was to install the top pieces:


7 out of the 8 went on smooth and lined up correctly. On one of them I had to add just a touch of a shim to one leg to level out the front edge.

That was it for the day, legs are tired and will probably be sore for tomorrow.

[DJPhatman]

CO, this is so epic of a build!

I am SOOO subscribed!

And you're coming along great. I wish I would have spoken up sooner, I would have advised you to put a 45 degree chamfer on the inside edge of the woofer baffle mounts. Easy as pie with the router and a chamfer bit.

[Grant Bunter]

CO, this is so epic of a build!

Absolutely!

I've got my popcorn and this is awesome...

[Scott Brochu]

Good save, that's why those tools are invented for.
The important thing is that you checked your work and caught it before it was too late.

[CoronaOperator]

I would have advised you to put a 45 degree chamfer on the inside edge of the woofer baffle mounts. Easy as pie with the router and a chamfer bit.

Too late now, lol. Although I'm not sure what that benefit would be? I'm using screws instead of blind nuts so I don't need the extra lip on the edge.

[CoronaOperator]

The important thing is that you checked your work and caught it before it was too late.

... and it will be checked again and again. Too much time and $$$ to get this wrong.

[CoronaOperator]

Not too much to post, did a half day in the shop on Friday. I used 3" brads to put the tops on and hold them in place until the glue dried. I just toe-nailed them from the feet. I learned that for toe-nailing brads if you hold the gun one way the brad will angle itself and curve upwards. If you hold the gun the other way, the brad will curve down and you will miss the top piece all together. The angle on the lead edge of the brad will guide it either one way or the other. I used vicegrips to pull all those brads after the glue dried and any other brads that had their tops sticking out. That allowed me to stack the cabs into my first (of many) tower of power pictures:



Then it was time to cut out all the half round back braces. My last radius' using the jasper jig was tearing out the top layer of ply. I was using a spiral up cut 1/4" bit and either the up spiral was tearing out the top piece from the shear force or the bit was a bit dull. Either way it came out like this:


So while shopping I picked up a new straight cut fluted 1/4" carbide bit. No spiral at all, just straight flutes. What a difference that made. The new cuts:

I wish I had that bit from the start although the old cuts won't show anyways after PL and bondo.

Since Harley made an appearance it was time to show everyone what a North American shop looks like. In NZ it is easy to keep a clean shop because all the sawdust and chips just fall upwards because they are on the bottom of the Earth. Over here everything falls down to the ground .



This is the table where I keep all the bits that I don't want lost in the sawdust:


That concludes week 2