1985 TransPlanar™ HP horns Ad

Blocking the Incoherent Wave

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Cast into the throat of every TransPlanar™ HP horn, unique beamwidth control vanes represent a revolutionary advance in constant-directivity design. Until now, two-inch-throat designs were compromised by on-axis dropout. Intrigued with this curious problem, E engineers applied principles of geometric optics to isolate the incoherent waveform responsible for this phenomenon. Instead of coursing down the horn in an organized fashion, this offending wave reflects off the walls of a two-inch throat, shadowing direct output and causing a loss in level. Ray analysis was used to predict this occurrence and determine the exact configuration of slotted waveguides which block the canceling wave and eliminate on-axis dropout.
Acting together with an optimum diffraction slot, the beamwidth control vanes also eliminate both horizontal and vertical beaming in the very highest octave. Other two-inch-throat designs exhibit narrowing of the coverage angle above 10,000 Hz. But the new HP horn maintains uniform dispersion to 20,000 Hz!
When Electro-Voice invented the constant-directivity horn in 1972, we really started something. Now we’re making waves again …introducing second-generation CD design with the most uniform beamwidth control in the industry. To learn more about the the new HP horn or the high-performance DH-1 and DH-2 two-inch-exit drivers designed especially for them, contact Pro Sound Marketing at Electro-Voice, 600 Cecil St.,
Buchanan, 49107. We’ll be glad to tell you why when the competition beams, we just smlle.