Very short midrange horn - effects?

[chris661]

So, I'm looking at building some 2x10" + CD PA top speakers, and one design I've spotted is a line array element from RCF, the HDL20A.

I note that, in order to reduce the cabinet width, they've put each 10" driver into a very short horn by angling the baffles back. My sims suggest that there'll be plenty of gain around 600Hz, with the expected comb filtering coming in a little over 1kHz. That's probably from cancellations arising from driving the horn with a relatively large cone on one of the walls. They cross over at 800Hz, which is fine for both the 10"s and the large compression driver.
One caveat I can see with the above design is rather narrow horizontal directivity heading towards the top of the 10"s range, as a result of having the drivers seperate.

One design I'm looking at involves putting the pair of 10" drivers into a fairly deep V-shape, but orientated so the drivers are firing a little off-vertical, a little like this EV sub below:

Both of the 10"s would be firing out of a ~10" square exit.

My question is this: what would the effect on directivity be if I was to use a small horn section like this?

I'm looking to put together a fairly straightforward, compact cabinet that'll keep frontal area small while using 2x10" midbasses and a 10" square horn. Angling the 10"s back so I come out with a frontal area of a little over 20"x10" would be a nice way to do it, and ought to outperform any other cabient of similar size.

I'll stop rambling now. Any guidance would be much appreciated.

Chris

 

[weltersys]

One design I'm looking at involves putting the pair of 10" drivers into a fairly deep V-shape, but orientated so the drivers are firing a little off-vertical, a little like this EV sub below:
My question is this: what would the effect on directivity be if I was to use a small horn section like this?

Chris,

A "V" horn of only 10" width will only impart directivity in the very upper range if crossed at 800 Hz.

 

[Top Shelf]

I have a similar setup that you're talking about but made with 2 , 6 & a half inch mids and 1 , 90x40 horn.

Take a look https://db.tt/MTeTTDJE

Very clean sounding according to the patrons.
The design also helps to get the compression driver voice coil in alignment with the midranges.

 

[chris661]

Thanks Art. I ran some sims in the Edge, which can do off-axis response plots. As you say, it doesn't appear to affect much in the operating range.
Unfortunately, Hornresp won't do a directivity sim for this cabinet type.

Jeremy, that looks the sort of thing. I'm planning on using a larger compression driver sat above the 10"s, though. Glad you're having good results

Thanks, all.
Chris