Scraping one idea and moving on

[athos56]

So I was looking at making a 3 way, having already made a Coaxial which I like. But the 3 way was getting out of hand. So now I'm thinking, of a 2 way.

One 15" (Eminence Delta 15a) in a 5.5ft^3 box. Which will reach up to ~1.5K, and one Radian 1" 475PB compression driver in a horn. Crossover would be at ~1.5K, I'm thinking just a drop in 1.6k crossover. The Port recomended is 4inches in diameter and .75in long, which would be the thickness of the MDF, (so no tube?)

Comments, criticisms?

[led7]

I'm no expert but I'd be concerned about pushing a 15" to 1.5 kHz.

led

[Pano]

Sounds like a plan to me. It will, at least, work.

Originally posted by led7
...I'd be concerned about pushing a 15" to 1.5 kHz.

Depends on the driver. I have heard a lot of bad 1" + 15" matings. However, my Selenium 15PW3-SLF 15" drivers sound surprisingly good up high. It doesn't have the same big 2K bump that the delta 15 does, though. Don't know what the Delta 15 sounds like.

My system crosses an octave lower - 800Hz. But to a big horn and 1.4" driver. That Radian driver looks up to the job at 1.6K no worries, depending on the horn. What horn do you have in mind?

A prebuilt crossover will get you started, but isn't going to be optimum, by any means.

[athos56]

The response curve that eminence lists with its 5.5ft^3 enclosure hits the -3db line above 1.5k so I figured it would be ok, but who knows how that translates into "sounding" at that frequency. I would crossover lower but that would mean a more expensive 1.4" or 2" compression driver. Maybe a shift up to the Delta Pro12 would be better (like my 3 way idea but with the compression driver taking over the mid-range) That idea, in a previous post, had a 500hz/5000k 3 way with a mid driver, and got to be to expensive. So maybe the 12 would be a better mate.

I'm clueless about horns, about the only thing I'm basing my judgment on now is whether or not its rated for loading below the crossover point. Here is one I have in my cart pending finalization of a plan.
http://www.partsexpress.com/pe/pshow...70-300&scqty=2

[Pano]

Originally posted by athos56
The response curve that eminence lists with its 5.5ft^3 enclosure hits the -3db line above 1.5k so I figured it would be ok, but who knows how that translates into "sounding" at that frequency.

Hard to say without hearing the driver. A lot of 15s have that big 2K rise. You might be ok if you underlap the crossover a good bit. I.E., you use a lower nominal frequency for the 15. Because it has so much energy at ~2K, you roll if off earlier and that results in an acoustic curve that is closer to what you want.

I'm clueless about horns, about the only thing I'm basing my judgment on now is whether or not its rated for loading below the crossover point.

That's a good place to start! But there does not seem to be a lot of consistency in rating that low point. At least I can't figure it out. You don't want to get too close the edge, though.

The horn you linked to looks like a CD (constant directivity) horn. Not the best sounding, though there are 1000s of them out there in cinemas all over the world.

You might be happier with something like this horn.

When designing your crossover don't forget that you will need to attenuate the horn and compression driver. Otherwise it will be much too loud. Generally this is done with an L-Pad. And there are some common tricks in the horn crossover to make up for the high end roll off. Though the Radian doesn't look bad.

The Usher 15s are on sale again at P.E. Pricier than the Eminence, for sure. But they just look so good in the photos. They keep calling my name.