Dayton 10" waveguide and D220Ti

[Andrew Eckhardt]

Here I have solved the problem of interfacing the 10" round PE horn with the Selenium D220Ti with an aluminum ring 5/8" deep. I've heard of using modeling clay and stuff and just didn't see that happening.

The included angle in the ring is over 12 degrees or so while the horn throat seems to be about 11. I had it matched but the horn throat was quite a bit steeper than that and after a bit of sanding I still had to make a decision about how to make it all meet.

I figure much more precision probably wouldn't equate to any improvement in sound quality, though a little more sanding might bring it in a lot closer. The camera flash makes the overhang look a bit bigger than it is.

The ring goes from .962 to 1.11". Mostly machined on a lathe. Ideally I'd have cut a curve into the ring but I don't have CNC on the lathe, yet.

Does the extra 5/8" throat length modify response at all?

[badman]

My own solution to this used a section of a 2L soda top (where the straight tubular top section transitions into the expansion to the larger tubular body), as it was able to match the driver exit angle well as well as being of the right diameter. I then filled and profiled the section of the horn that this influenced. Your solution will likely create a slight amount more top end pattern collapse and bottom end extension. Slight as in... only noticeable with good measurements.

Nice work!

[Andrew Eckhardt]

Thanks for the compliment. I think it will work ok then. I'm trying to stuff this thing in the middle of a Beta 8A and an APT80. So maybe 2-6kHz. 2.2k 24dB oct electrical in the interest of power handling if the 8A doesn't go crazy up that high. Just have to see how it runs.

[Gary P]

I've got a pair of the 12" waveguides. The fit to screw on drivers is just as bad as what you are showing here.

My thought on a work around is to purchase the bolt on version DT220Ti and purchase the Selenium 1" bolt on to 1" screw on adapter. The inside of the adapter could be machined to match up with the wave guide.

Any negatives to this method?

[SunRa]

The screw on adapter should be thick enough to allow for machining the needed contour.

This is the adapter?

[Gary P]

Yep, that's the one.

[Andrew Eckhardt]

I thought of that, but hadn't assessed the problem until after ordering the thread-on drivers. As it stands I need to glue on a sleeve that holds a new complete set of threads because the 5/8 long adapter ring takes up all the original ones. Not a big deal with some donor horns around, some extra PVC, and all purpose cement.

Making the bolt-thread adapter work means a bigger angle in a shorter throat, unless you can cut a curve neatly or like filing. Maybe that would be better for top-end performance, I don't know.

[CLS]

Originally Posted by SunRa

...

This is the adapter?

I own that, too, for several years now, but I've not used it yet. No access to a proper lathe is a major reason, but there's another problem.

Don't know what you get. The ones I bought got very odd dimensions. The inner diameter of the entrance (to mate the driver) is 26.5mm, and 25mm for the exit (to horn throat).

It's shrinking, not expanding! And the opening for mating with driver is not correct, thus a step is inevitable, at the very critical position

I hate adapters