8 x DR250 build

[CoronaOperator]

I finally got all the PVC reflectors mounted . They took awhile as I had to custom mold all 32 of them to the right diameter as I couldn't find any PVC schedule 40 pipe in stock so I had to use PVC sewer pipe. I hope that doesn't make my DR's sound like sh@t. There was a sign for the schedule 40 next to an empty shelf. I asked about it and the guy said they weren't getting anymore in stock. It is either a seasonal thing here (winter time here now) or they are phasing out PVC as I couldn't find any PVC couplers for the vents as well although they did have the 2" pipe. So, for the vents I went with ABS as they did have that in stock. The hot melt doesn't stick as well to the ABS as the PVC but I think I'll be OK.

The flex in the horn sheaths was bothering me so I added some 5/8" x 1/8" strips again leaving plenty of room for the vent and I left out the middle section as the middle brace will support that:

Even though the strips are only 1/8" wide x 5/8" tall, the difference is substantial when you push on them or knock on them. It sounds and feels solid now. I was originally going to put another strip on top of them to make an "I beam" but it wasn't necessary. I didn't cut out the radius or fit them precisely, just lots of PL to fill the gaps. I let that set up overnight and then the next day went in with a syringe filled with PL to fill any missed spots.

I then did some bodywork to everything but the outside of the cab. I filled all the staple holes, sanded and filled any joint lines and pretty much got everything ready for paint as I will be painting everything without a grill. I know there are panels yet to add but the random orbital won't be able to get everywhere once those panels are attached:

Scrape the excess glue, sand it a bit, and you're good to go. I make them pretty just because I'm doing for somebody else who's paying me.

Well that quote didn't make me feel any better, lol. Trying to sand hotmelt in that spot wasn't working and it was bothering me so I got a little carried away with the bondo:

Not that great of a picture but that joint is smooth now!

I guess that's the end of that phase. Next up will be the compression horns and modules. I might need some luck to figure those out !

[Bill Fitzmaurice]

Well that quote didn't make me feel any better, lol. Trying to sand hotmelt in that spot wasn't working and it was bothering me so I got a little carried away with the bondo:

Not that great of a picture but that joint is smooth now!

It didn't matter anyway. For any obstacle or irregularity in the horn path to have a meaningful effect on response it must approach a wavelength in dimension. The LF horn only runs to 2kHz, where a wavelength is almost seven inches.

[CoronaOperator]

It didn't matter anyway. For any obstacle or irregularity in the horn path to have a meaningful effect on response it must approach a wavelength in dimension. The LF horn only runs to 2kHz, where a wavelength is almost seven inches.

Acoustically yes, however I worked as a painter/drywaller to get myself through college. Everytime my hands and eyes went over that little bump it sent shivers through my spine. Regardless of what the logic said (I did that calculation roughly in my head), once you put some filler in one hand and a knife in the other "Francesco the Painter" comes out. If little rocks tied to RCA cables make some people hear the mids more clearly then getting that bump off my mind will make me feel better.

[NukePooch]

I hit the link to the pebbles. First I'd ever heard of it. That really seems legit! I put an order in for $500 worth so's I can clean up my sound. Now, if I can just win tha ebay auction for those NASA certified rocks from the planet Neptune, I'd have it all together.

[Bruce Weldy]

I hit the link to the pebbles. First I'd ever heard of it. That really seems legit! I put an order in for $500 worth so's I can clean up my sound. Now, if I can just win tha ebay auction for those NASA certified rocks from the planet Neptune, I'd have it all together.

+1

I often fill up my truck bed with as large'a boulders as I can....then I position them in very strategic areas around the places I play. What's funny is that the silly people in the crowd don't have a clue how important they are to the sound....all they do is sit on 'em.....neanderthals....

[ripNdeb]

In for three xtra large

[CoronaOperator]

Well, I tried the rocks and didn't get the improvement I was looking for , so back to building the DR's.

I laid down parchment paper and cut out and glued the module flanges in place. I used 6 screws to hold everything tight while the PL dried. The parchment paper worked really well, once the flanges were dry the paper peeled cleanly. Next up was the faces for the compression drivers. I used hot melt just on the top edge to secure them instead of screws. I did one side at a time and that allowed me to wiggle them exactly where I wanted them. As the glue slowly hardens the amount of movement you can move them gets reduced so by the time it gets hard the positioning is just right. The plans suggest screws but I'm sure I would have swiss cheese by the time I had them in the right spot. With the hot glue I could also heat it up with a heat gun to re position them.



Next up were the cleats. Boy were these ever a pain to cut out. Some tilted left, some right, some straight. I eventually just gave up any sort of precision, eyeballed them long, trimmed until they were in the ballpark, then relied on the magic of PL to make everything better. I'd say these modules are now about 20% PL / 80% wood.


It might have just been a bad day in the shop but eventually I managed through them. I used a heat gun to re melt the hot melt glue to seperate them after the glue dried.


Next I decided to build the high frequency array. When all my massive PL expanded and dried on the last step, the 2 center cleats slightly bowed out the faces. Nothing too bad but I want to mount the arrays first before I put the sheaths on as the sheaths will lock in the bow.

Here is how I made the 60* cut:

I titled the arbor to 30*, then placed the fence right up tight to the blade on the left side of the blade. I clamped a board on the right side 1/2" from the fence to make a slot just to keep the workpiece tight against the fence. Then I just pushed the work piece through. It worked like a charm with no issues.

After I cut out all the blanks, I made a jig to cut out the little pieces. I placed a fresh piece of chloroplast underneath to see the cutline on the saw and give a bit of a zero clearance insert. Then, I used scraps brad nailed to the miter sled to hold the piece in place:


The little triangle piece is held with only one brad so that I could swivel it over the work piece to hold it down. I needed to use a screwdriver on the other side to hold that end down.

After that I sanded all the parts with 120 grit with a orbital sander:


I managed to glue up one of the arrays today. Boy that isn't very fun. Once you put PL on the little pieces they slide all over the place. 7 more to go...

[CoronaOperator]

Those little array pieces were slippery once you put the PL on as the PL was almost like grease. I made a little hardboard cutout to help me position them so I could get a brad nail in them and just clamped it in place:


That helped me get these things together quickly:


Here, the arrays are not mounted to the modules but just for fun I wanted to see how they looked in position:


They have come a long way!, I think they might make it to the finish line yet !

[heavybdrums]

awesome build CoronaOperator. Just beginning on mine, got some plywood today, Can't wait until mine get to the point yours are, looking like some space modulated deconfabulator death array

[J_Dunavin]

OOOOO I love the comp tweeter arrays!!

[heavybdrums]

a question for the DR250's. I have started on mine and have not cut the corners off the woofer spacers. I was thinking I liked the extra area of contact, but some questions about this have arose, as regards chamber space being reduced by not cutting off these corners. I figured it was just to save weight (lol), but now that the spacers are still accessible I thought I would ask before going much further if this would be a problem.

[Bill Fitzmaurice]

It won't be a problem, just unnecessary weight.

[CoronaOperator]

a question for the DR250's. I have started on mine and have not cut the corners off the woofer spacers. I was thinking I liked the extra area of contact, but some questions about this have arose, as regards chamber space being reduced by not cutting off these corners. I figured it was just to save weight (lol), but now that the spacers are still accessible I thought I would ask before going much further if this would be a problem.

Cool! Another DR250 build. I was starting to think I was all alone here. You should start a build thread for it! The more the merrier!

PS: Two Words ....... "Brad Nailer"

[DJPhatman]

Two Words ....... "Brad Nailer"

And, he ain't talkin' MOVIE STARS, neither!

[escapemcp]

And, he ain't talkin' MOVIE STARS, neither!

Porno Star? Boom-chikka-wahhh