[. . . ] HP64 General Product Description The Electro-Voice® model HP64 is a wide-range, flat-front, high-frequency, constant-directivity horn. [. . . ] The horn shall possess a throat of 4. 92-cm (1. 94in. ) diameter and its flange shall be provided with four ¼20 clearance bolt holes on a 10. 2 cm (4. 0 in. ) circle for the mounting of the compression driver. The horn shall be 27. 9 cm (11. 0 in. ) high, 22. 2 cm (8. 8 in. ) wide, and 22. 2 cm (8. 7 in. ) long. The horn shall be the Electro-Voice model HP64 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). Horizontal Beamwidth: 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: 60° (+30°, -10°) (-6 dB 1. 7 kHz to 20 kHz) Vertical Beamwidth: 40° (+20°, -10°) (-6 dB, 1. 8 kHz to 20 kHz) Directivity Factor R (Q): Bolt on; standard 2" diameter throat, 5" diameter mounting flange and four clearance holes for 1/4" bolts on a 4" diameter bolt circle. (See Figure 1). Recommended Driver: 18. 1 (average 1. 6 kHz to 20 kHz) Directivity Index Di: DH1A, DH2A Weight: 12. 6 dB (+0. 9, -2. 9 dB) 10 log R, (average 1. 6 kHz to 20 kHz) Lowest Recommended Crossover Frequency: 2. 5 kg (4. 5 lb) 1000 Hz Dimensions: A B C D E F G H Inches 1. 938 5. 00 8. 75 11. 00 4. 00 0. 281 x 4 8. 68 8. 49 Figure 1: Dimensions Directivity Beamwidth The axial directivity factor R (formerly Q) of the HP64 horn was computed at each one-third-octave center frequency from the horizontal/vertical polars. The graph in Figure 2 illustrates this data over the range 630 Hz to 20 kHz. [. . . ] 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. [. . . ]