Dayton CX150-8 Coaxial Project

[4thtry]

I'm now up to a stereo pair of curved cabinets, flush trimmed & almost ready for some sanding and finishing:

[4thtry]

Here's a look inside the 5.25" midrange cutout, showing the 4 non-parallel sides. The rough texture to the left side is the bottom of the 1st layer of 1/8" tempered HDF material. The front & back panels are parallel, but these parallel surfaces will be broken up somewhat by the midrange magnet & basket assembly. I'm also thinking about gluing a small cone, protruding inward, to the surface of the back panel to break up the parallel surfaces even further. (25 second exposure, F18, ISO 200, small LED flashlight hidden inside left side of enclosure)

[4thtry]

Here's a tip for those needing to print something large and only have access to standard 8-1/2x11 printers: Matthias Wandel at woodgears.ca (a very fun woodworking site) offers a free version of his BigPrint program for your PC. It allows you to print just about anything you could possibly need onto several sheets of standard printer paper, with a background grid of diagonal lines to act as registration marks. You just overlap the prints until all your lines and diagonals line up, and tape the sheets of paper together. The free version will print the word "eval" (as in "evaluation") on each sheet, which is non-intrusive, and is otherwise exactly the same as the version he offers for sale (cheap!). Check it out here: http://woodgears.ca/bigprint/index.html
Could be helpful!

Thanks for the tip. I actually did something similar to this for my Linehopper speakers (see post 5 of my signature thread). I loaded a full scale picture of Paul K's drawing into photoshop and then added horizontal and vertical grid lines manually. I then printed it out onto a large number of 8.5x11 sheets. But it was a lot of work to manually create the grid lines and then line everything up. Your idea seems much better.

[ttan98]

Hi 4thtry,
I look through most of the postings here, there is no mention of the x-over design for your Coaxial driver, have you design one yet or in the process of designing one, can you share with us the design. Thanks.

[4thtry]

Hi 4thtry,
I look through most of the postings here, there is no mention of the x-over design for your Coaxial driver, have you design one yet or in the process of designing one, can you share with us the design. Thanks.

Yes and No. Yes, I have put together a tentative crossover based on some FRD and ZMA measurements that I made with the drivers mounted in a pair of rather crude looking test boxes. I cobbled these test boxes together in an attempt to simulate the finished enclosure. I did not post this information because my measurements included a huge response irregularity caused by a thick adapter ring that I used to mount the midrange driver.

My current plan is to wait until I have the boxes completed so that I can take measurements that will include the baffle step, round over, as well as any other response changes caused by my internal and external cabinet shape.

Right now, I am getting close to the point where I can mount the drivers and run up a new set of measurements. But, I am still waiting on my Walnut hardwood order, and I need this wood to finish the baffle boards (double thickness with 3/8" round over). I will share my design and post my XSim model and crossover as soon as I get to this point. But I may end up with the cabinets primed & finished before I am able to do this.

Bill

[tom_s]

Those are looking so cool! I haven't read the whole thread, but do you think you'll need outriggers?

[ugly woofer]

Looks great Bill, have you considered veneering the front with a straight grained wood species to make the curves even more apparent.?

[ttan98]

Yes and No. Yes, I have put together a tentative crossover based on some FRD and ZMA measurements that I made with the drivers mounted in a pair of rather crude looking test boxes. I cobbled these test boxes together in an attempt to simulate the finished enclosure. I did not post this information because my measurements included a huge response irregularity caused by a thick adapter ring that I used to mount the midrange driver.

My current plan is to wait until I have the boxes completed so that I can take measurements that will include the baffle step, round over, as well as any other response changes caused by my internal and external cabinet shape.

Right now, I am getting close to the point where I can mount the drivers and run up a new set of measurements. But, I am still waiting on my Walnut hardwood order, and I need this wood to finish the baffle boards (double thickness with 3/8" round over). I will share my design and post my XSim model and crossover as soon as I get to this point. But I may end up with the cabinets primed & finished before I am able to do this.

Bill

Thanks looking forwards to viewing your x-over and your impressions of this drivers.

[4thtry]

Those are looking so cool! I haven't read the whole thread, but do you think you'll need outriggers?

Thanks. The base is 15x12.5" and it seems fairly stable without drivers. The crossover will go in the bottom and when the woofer is mounted, outriggers will probably not be needed. But I could add them later just to improve the overall appearance.

[4thtry]

Looks great Bill, have you considered veneering the front with a straight grained wood species to make the curves even more apparent.?

No, I had not considered this. The front will be solid 3/4" thick walnut, grain running from top to bottom. The curved panel (and the rest of the box) will be finished in high gloss almond to contrast against the deep, dark walnut. I could add racing stripes of another wood type, for contrast. But my initial plan was similar to what John H did with his Philips TV speaker project. He used a solid walnut baffle contrasted against a very light colored cabinet. I think John has a thread for this project, I will see if I can find it.

[jhollander]

No, I had not considered this. The front will be solid 3/4" thick walnut, grain running from top to bottom. The curved panel (and the rest of the box) will be finished in high gloss almond to contrast against the deep, dark walnut. I could add racing stripes of another wood type, for contrast. But my initial plan was similar to what John H did with his Philips TV speaker project. He used a solid walnut baffle contrasted against a very light colored cabinet. I think John has a thread for this project, I will see if I can find it.

Bill I think you have the pictures from Iowa, which are way better than the thread!

[4thtry]

Found it. This is the look that I am trying to duplicate:

[JavadS]

I'm a fan of the solid hardwood baffle (or whole speaker for that matter), you have my vote =)

[4thtry]

The only worry is seasonal expansion/contraction. To deal with this, I will be breaking the hardwood baffle into two parts. An upper baffle for the midrange and a lower baffle for the woofer, separated by about 2 to 3 inches by a hardwood nameplate. Gluing or bolting the hardwood baffles to the 3/4" particle board inner baffle should help to stabilize the hardwood.

[4thtry]

I did a 3/8" round over on all non-baffle edges. Then I sealed the raw cabs with several coats of Sealcoat sanding sealer, smoothing out the surface with 100/200 grit between coats. After the sealer dried, I skim coated all flat surfaces and edges, except the baffle, with bondo. When this is sanded smooth once again, I will be ready for primer. I will be using the same oil based primer and gloss enamels that I used for the Linehoppers. Several coats of Rustoleum's oil based clean metal primer sprayed with a 1.8mm tip. Then several coats of Rustoleum's Gloss Almond oil based protective enamel, again, sprayed with a 1.8mm tip.