How does the diffraction horn work??

[Chips and Palsa]

Hey guys! a quick question about the wooden compression driver horns. Please stop me if I'm asking too much about Bill's IP but how does, what looks to me like a horn with a very high horizontal dispersion and a narrow vertical dispersion that is turned on its side give 100 degrees of horizontal dispersion???

I had looked up an article on horn theory to read through but thought id ask the experts and possibly even the designer.

The reason I asking is that I really liked how another forum member's (djtecthreat) OT12's turned out using this single Goldwood horn:



I'm finishing up my first 2512 Melded OT12 now, and would make a matching one before considering a different HF section, but If I were to build more cabs in the future I would definitely look into using this horn and a selenium D220 driver if the dispersion wasn't substantially lower.

looking at the front of the horn mouth however, It seems like I'd be loosing some.

Leland had said that they used to be DR horns, I would guess the 300 based on the picture?

Just looking for some input as to whether or not this would be advisable and any downsides if so. A little explanation on how the wooden horn pulls that awesome horizontal dispersion would be awesome too

Thanks in advance!

[Bill Fitzmaurice]

Hey guys! a quick question about the wooden compression driver horns. Please stop me if I'm asking too much about Bill's IP but how does, what looks to me like a horn with a very high horizontal dispersion and a narrow vertical dispersion that is turned on its side give 100 degrees of horizontal dispersion???

Just like all sound sources the horizontal angle of dispersion of a horn is inversely proportional to the width of the horn, unless you do some finagling with the horn geometry to force the sound waves to do what they inherently don't want to. This shows why:
http://www.acoustics.salford.ac.uk/fesc ... slider.swf

A better question is how does a horn that is wide deliver wide dispersion? The answer is said finagling of the horn geometry. I originally used standard horns rotated vertically in the DR300, as there are no widely available diffraction horns that will work, but abandoned that in favor of those now in the plans.

[Chips and Palsa]

Just like all sound sources the horizontal angle of dispersion of a horn is inversely proportional to the width of the horn, unless you do some finagling with the horn geometry to force the sound waves to do what they inherently don't want to. This shows why:http://www.acoustics.salford.ac.uk/fesc ... slider.swf

Somewhat counterintuitive but that link helps!

I would be orienting that horn vertically as done in the DR300 as well.

The only reason I ask is for ease of repeatability and OCD concerns; I'd drive myself nuts if I couldn't get the wood horn perfect so I thought this would we a way around it!

How was the horizontal dispersion in the DR300s with that horn?

[Bill Fitzmaurice]

How was the horizontal dispersion in the DR300s with that horn?

Not as good as with the current version, but since DR300 is intended for use at long distances where wide dispersion isn't a major concern it didn't matter that much. BTW, if you use the pictured horn in the OTop 12 you lose high frequency coupling when stacked.

[dswpro]

You should come hear my Otop 12's some time. I'm in Medina but use them frequently in Akron / Canton. I've 2 melded and 2 with the wood horn and Selenium drivers. ( Which I prefer) PM Me of you want to get together some time.

Don Sullivan