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Hersteller: Electro-Voice Dateigröße: 421.35 kb Dateiname: Unterrichtssprache:

This design provides the following features and benefits: a) A proper flare, assuring a correct low-frequency acoustic impedance match to the horn. b) Simple, strong horn mounting, saving costly installation time, and eliminating complex and unattractive hardware. RECOMMENDED HORNS The following Electro-Voice horns are recommended for use with the DH2A/DH2A-16: HP64, HP94, HP420, HP640, HP940, HP1240, HP4020, HP6040 and HP9040. CROSSOVER AND EQUALIZATION As with all horn/driver combinations that combine high overall efficiency with constant directivity, the DH2A/DH2A-16 and HP series horns provide “raw” or unequalized frequency response that rolls off above 3,000 Hz or so at about 6 dB per octave. Figure 3 shows the DH2A/DH2A-16 on an HP9040 horn, with and without equalization. The equalization has been provided by an Electro-Voice XEQ-2/XEQ-3 crossover/equalizer equipped with the EQU equalization module. While the equalization of a constant-directivity horn/driver combination can be achieved with a conventional one-third-octave equalizer, the use of the XEQ-2/XEQ-3 crossover/equalizer with the appropriate accessory EQ module is recommended. This way, the broadband equalization required by the horn/driver combination is supplied by the crossover/equalizer network, and the one-third- octave equalizer can be devoted to correcting the more subtle room- and array-related response anomalies. The following EQ modules are available for the DH2A/DH2A-16: Module Horn(s) EQO HP9040 EQR HP940 EQS HP1240 EQT HP640 EQU HP4020; HP6040 EQV HP420 EQW HP64, HP94 Refer to the XEQ-2/XEQ-3 engineering data sheets for more information on XEQ-2/XEQ-3 performance and application. For passively crossed over systems, the XEQ804 and XEQ808 crossover/equalizers are available. FIELD REPLACEMENT In case of voice-coil or diaphragm failure, the diaphragm cover subassembly can be replaced by just removing the driver from the front housing, then replacing the cover subassembly itself by the removal of six cover screws. A replacement kit with instructions may be ordered under Electro-Voice Part No. 81161XX (DH2A) and 82816XX (DH2A-16) from the Electro-Voice Service Department in Buchanan, Michigan. If desired, the complete driver may be returned for service. AES RECOMMENDED PRACTICE The DH2A/DH2A-16’s specifications conform to the AES Recommended Practice for Specification of Components Used in Professional Audio and Sound Reinforcement (AES2-1984; ANSI S4.26-1984). This recommended practice was developed over a number of years by consultants, manufacturers and government agencies from around the world, so that the detailed performance information required in professional applications could be provided in a unified format. The recommended practice has been published in the October, 1984, issue of the Journal of the Audio Engineering Society (vol. 26, pp. 771-780). Individual copies of the recommended practice are available from the Audio Engineering Society, 60 East 42nd Street, New York, New York 10165, USA. Also appearing in this issue is an article which comments on the recommended practice from an engineering point of view (C.A. Henricksen, “Engineering Justifications for Selected Portions of the AES Recommended Practice for Specification of Loudspeaker Components,” pp. 763-769). The comments in this article will be particularly of interest to those not involved in the day-to-day design and testing of loudspeakers. ARCHITECTS’ AND ENGINEERS’ SPECIFICATIONS The loudspeaker shall be of the compression-driver type consisting of a 0.002-cm (0.012-in.) thick titanium diaphragm joined to an edge-wound aluminum ribbon voice coil on a polyim-ide form. The nominal impedance shall be 8 ohms (DH2A) or 16 ohms (DH2A-16). The loudspeaKer shall exhibit essentially flat power response from 500 to 3,000 Hz, with a smoothly rolled-off response from 3,000 to 20,000 Hz. Its efficiency shall not be less than 25%. Its sensitivity, when mounted on an EV HP4020 horn, shall be 115 dB (1 W/1 m) with a 500-to-5,000-Hz pink-noise signal applied. The loudspeaker shall be capable of handling a 30-watt, 800-to-20,000-Hz pink-noise signal with a 10-dB crest factor (300 watts peak) for a period of 24 hours. In addition, it shail be capable of handling a 40-watt, 800-to-8,000-Hz pink-noise signal and a 60-watt, 1,500-to-15,000-Hz pink-noise signal, with 6-dB crest factors for a period of two hours in both cases. The loudspeaker shall have a diameter of 17.1 cm (6.75 in.) and a depth of 18.7 cm (7.38 in.). It shall have a 1.94-inch throat opening, with four '/4-20 threaded bolt holes on a 4-inch-diameter circle for mounting. The unit shall weiqh no more than 7.2 kq (15.8 lb). The loudspeaker shall be the Electro-Voice model DH2A (DH2A-16) compression driver. WARRANTY (Limited) Electro-Voice products are guaranteed against malfunction due to defects in materials or workmanship for a specified period, as noted in the individual product-line s...

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