Conical Confusion [message #18822] |
Thu, 17 August 2006 19:12 ![Go to next message Go to next message](/forum/theme/AudioRoundTable/images/down.png) |
PointSource
Messages: 28 Registered: May 2009
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Chancellor |
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Theories & opinions, please! One reputable designer states that a (square or rectangular) conical horn exhibits little or no pattern control over its chosen frequency band, and that the horn wall angle has almost no impact on the horn's dispersion. Another reputable designer states that a conical horn exhibits pattern control that's tight enough to use in a horizontal array. Any input welcome!
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Re: Constant Directivity [message #18826 is a reply to message #18825] |
Fri, 18 August 2006 01:10 ![Go to previous message Go to previous message](/forum/theme/AudioRoundTable/images/up.png) ![Go to next message Go to next message](/forum/theme/AudioRoundTable/images/down.png) |
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Wayne Parham
Messages: 18748 Registered: January 2001
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Illuminati (33rd Degree) |
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Well, a lot of what you said is general and not specific enough to really analyze. But there are a few concrete facts you can get a hold of.If a horn is short, it will not load down to as low a frequency as a longer horn of the same shape. If its mouth area is small, then it won't have as good pattern control as a larger horn. Beaming is another name for collapsing directivity and it occurs when a direct radiator becomes directional because of path length differences between points along its cross-section and listening points out in the environment. It occurs in a curved wall horn because wall angle gets narrower further down the throat. I might suggest for you to study horn theory and learn how things work. The concepts are pretty simple so you can pick it up pretty quickly.
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Re: Constant Directivity [message #18827 is a reply to message #18826] |
Fri, 18 August 2006 21:06 ![Go to previous message Go to previous message](/forum/theme/AudioRoundTable/images/up.png) ![Go to next message Go to next message](/forum/theme/AudioRoundTable/images/down.png) |
PointSource
Messages: 28 Registered: May 2009
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Chancellor |
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I've gleaned some basics from various websites (plus a few finer points here & there), but such seemingly disparate conclusions from two reliable sources left me wondering if I'd missed some glaringly simple horn principle. (Of course, the hit-and-miss educational system leaves much to be desired!) I know, I should download the McBean program; it'll have to wait until I can afford to add a PC-type computer. Does the throat area have anything to do with where the horn begins to beam? I've seen a few designs --mostly for 10" cones-- where the throat looked like the CD slot one would find in a 2" horn. Is this a similar diffraction technique? Oops! SG1 200th episode begins, gotta go! Later!
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Re: Constant Directivity [message #18833 is a reply to message #18828] |
Sat, 19 August 2006 19:34 ![Go to previous message Go to previous message](/forum/theme/AudioRoundTable/images/up.png) |
PointSource
Messages: 28 Registered: May 2009
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Chancellor |
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Thanks for the input, Wayne. I have a basic grasp of most of your response, though I've never heard of the "throat angle" concept before now. I'm beginning to think that throat geometry has more impact on a horn design than any other single variable. BTW, if I can avoid mucking about with phase plugs, I won't feel like I've missed anything!
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