[. . . ] HP42S TransPlanarTM Constant-Directivity Horn General Product Description The Electro-Voice® model HP42S is a wide-range, flat-front, high-frequency, constant-directivity horn. [. . . ] The horn shall be the Electro-Voice model HP42S constant-directivity horn. Specifications: The following specifications are in accordance with or exceed the AES Recommended Practice for Specification of Loudspeaker Components Used in Professional Audio and Sound Reinforcement (AES2-1984; ANSI S4. 26-1984). 40° Vertical Beamwidth: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18. 1 Directivity Index Di: 12. 6 dB 10 log R, Lowest Recommended Crossover Frequency: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1000 Hz Construction: Polyester resin and glass-fiber laminate integrally molded to a die-cast zinc throat section. This hybrid construction assures a rigid driver mount, accurate, loss-free throat-wave transmission and low total weight compared to horns of similar size. Mechanical Connection of Driver: Bolt on; standard 2" diameter throat, 5" diameter mounting flange and four clearance holes for ¼" bolts on a 4" diameter bolt circle. [. . . ] For customer orders, contact the Customer Service department at 800/392-3497 Fax: 800/955-6831 For warranty repair or service information, contact the Service Repair department at 800/685-2606 For technical assistance, contact Technical Support at 866/78AUDIO Please refer to the Engineering Data Sheet for warranty information. [. . . ]