I've noticed that very few designers bother with a conical horn for a 1" or 2" compression driver. I'm aware, though marginally, that a conical doesn't load well near its lower cutoff, so does this mean that a larger horn is needed to achieve the same cutoff as (for instance) a smaller CD-type horn?

I've also observed two characteristics of the Danley-designed 1" conical horns (ignoring the tapped-horn components for now). One, is the fact that they're VERY big; two, is they all have fairly narrow coverage patterns (40-50 degrees). I know that the horn has to be large enough to house the other speakers, but how much of it is needed to load the 1" driver?
And, if the coverage pattern were opened to 90 degrees, what might be expected for an off-axis response? Will it become beamy?

Having failed to find a HF horn which meets my criteria for coaxially mounting in the mouth of a conical midbass horn, I had thought to design my own from plywood.

Any experience in this area will be met with adulation!

Yes a conical horn will start cutting off appox. 20% higher in frequency than what the flare rate is. So you would need a larger horn to achive the same cutoff.

::I know that the horn has to be large enough to house the other speakers, but how much of it is needed to load the 1" driver?

I have no idea.

::And, if the coverage pattern were opened to 90 degrees, what might be expected for an off-axis response? Will it become beamy?

It would hold its pattern down the the cutoff of the horn but off-axis the higher freqencies would be more jagged in response and at a lower level. All horns start to beam at a higher frequency especially a conical horn (But I don't remember what the formula is). CD horns try to stretch the beaming out effect to the upper octaves where the ear's not a sensitive.

My intent is to stack (vertically) two 1" compression drivers on narrow or otherwise smallish 90-degree horns within the mouth of a 1x10" conical midrange horn of my own design, for line array purposes. Thus far, the horns available either obstruct too much mouth area, or don't span the midhorn's height for coupling to the next unit. (Using a pair of HF drivers per enclosure better approaches the "dense interference" tactic.)

I really don't want to change the mouth ratio by shortening the height. This has led me to consider the possibility of home cooking the HF horns, but the design needs to be simple, meaning no curved flares. Maybe adding a diffraction slot would work....

It's the 10" diameter DDS ENG 1-90 waveguide, which is back in production under DDS's new owners in Texas. The off-axis response declines gently and uniformly out to 45 degrees from the centerline, so the power response is very good. There's a little beaming in the top octave but it's less noticeable than with a direct radiator 1" dome because the pattern doesn't widen much at lower frequencies.

I'm not sure that a CD horn really has worse pattern control at its bottom end than other types; I think that a non-CD horn's variable pattern sort of "masks" the breakdown of pattern control whereas it's easier to detect the transition with a CD horn.

I like to match up the pattern of horn and woofer in the crossover region as closely as is practical, so I don't use 40 or 50 degree horns, CD or otherwise.

All else being equal, smaller and/or shallower horns will have less audible reflections within the horn itself - another argument in favor of wide-pattern horns.

Duke

I've already considered the ENG 1-90, but a pair of them stacked would be taller than my midhorn design unless they were each trimmed flat on one side and adhesed together. With a pair per box plus modifications, that would become very cost prohibitive for a 3- or 4-box line array (per side)!

The design is already a bit large so I'm hesitant to enlarge the mouth unless it's necessary, and I'm afraid to make it shorter due to increasing diffractive effects. Decisions, decisions!

I didn't realize this was for a line array. Nope, I don't think the ENG 1-90 would work well in that sort of application.

Hmmmm.

DDS makes a two-horn stackable array that might be of interest, but I have zero experience with it.

Sounds like this is a very ambitious project!

Duke

• http://www.ddshorns.com/catalog.php?page=DSLA1100

I was intimately familiar with DDS for a number of years before I retired from live audio about 8 years ago. Their factory was a half hour drive from my home, and I would drop in now & then to BS with Pat and Bob (the original owners). They would emerge --or, float-- from their shared office, usually followed by a billowing cloud of smoke. They even did some TEF analysis for me on a monitor I designed using one of their horns and McCauley drivers. (The McCauley brothers, also in this area, were another story....)

In reality, the designs are ambitious but the projects are not. When I'm satisfied with these loudspeaker systems on paper (there's a couple more on the drawing board), I will simply share them with the Forum in appreciation for all the help I've received here toward their development. I can't afford to build them myself, but if anyone sees any promise in my amateur doodlings, they are free to build and modify as they wish!