User manual ELECTRO-VOICE 312B DATASHEET

[. . . ] The frequencies above 1, 250 Hz are handled by the Electro-Voice HP640 constantdirectivity horn, in combination with a contractor-selected-and-installed high-frequency compression driver. Ring-Mode Decoupling (RMDTM) Technology The 312B controls both acoustical and mechanical ring modes to provide dramatically increased intelligibility, using techniques learned from the development of the Electro-Voice X-Array concert speakers. There is much less coloration of the sound from resonating sources, leaving only the intended sound to be heard by the audience. Installation The 312B is designed to be suspended safely and easily. [. . . ] At higher frequencies, the roll-off approximately matches the power-response of the DL10X-SH (6 dB per octave). At lower frequencies, directivity is lost when the mouth is no longer large enough to maintain directional control. These two consequences can be observed in the "humped" response in Figure 3. Equalization can be easily applied with a graphic equalizer to give a flat response. The high-frequency compression driver can be equalized with a graphic equalizer or an EQ module inserted into the Electro-Voice XEQ-2 (two-way) or XEQ-3 (two-way or three-way) active crossover/equalizer. The EQ module should be selected to suit the particular compression driver and the HP640 horn (see relevant data sheet). Because of its use in large arenas, where air loss can be significant, it is recommended that the system be equalized "on site" for optimum results. The XEQ-3 and the mid-bass EQ module from the EQMT-2 can be used to provide a good starting point for the equalization. Electro-Voice strongly recommends the use of a 100-Hz high-pass filter to protect the drivers from unnecessary excursion and thermal stress. Directivity The axial directivity factor R q of the 312B was computed at each of the one-third-octave center frequencies over the frequency range noted from the horizontal/ vertical polars shown in Figure 7. Directivity index (Di) was taken over the same frequency range. The amplifier is set to provide 600 watts into the 3. 45-ohm EIA equivalent impedance (45. 5 volts). Amplifier clipping sets instantaneous peaks at 6 dB above the continuous power or 2, 400 watts peak (91. 0 volts). During this test, the mid-band section is not high passed at 1, 250 Hz. The highfrequency section's power handling is dependent on the selected driver combination. Please refer to the relevant engineering data sheet. Architects' and Engineers' Specifications The horn shall be of the constant-directivity type. It shall produce a horizontal beamwidth (6-dB-down angle) of -60°, deviating no more than +10° or ­20° from this angle over the range of 400 Hz to 20 kHz. It shall produce a vertical beamwidth of 40°, deviating no more than +20° or ­15° over the frequency range of 325 Hz to 20 kHz. In addition, it shall provide an acoustic load to below 100 Hz. The 312B mid-bass section shall operate over the range of 100 Hz to 4, 000 Hz, with a recommended crossover frequency of 312B Coaxial Constant-Directivity Manifold Technology® Horn System 2 312B Coaxial Constant-Directivity Manifold Technology® Horn System 1, 250 Hz, and be driven by two 10-inch, weather-resistant drivers with high-technology cones of Kevlar® and epoxy. 1 The patented Manifold Technology® technique shall be exploited and result in a power-handling capacity of 600 watts per EIA Standard RS426. The average axial sensitivity shall be 105 dB SPL at 1 meter with 2. 83 volts applied. [. . . ] A list of authorized service representatives is available from Electro-Voice Service at 600 Cecil Street, Buchanan, MI 49107 (800/234-6831 or FAX 616/695-4743). Incidental and Consequential Damages Excluded: Product repair or replacement and return to the customer are the only remedies provided to the customer. Electro-Voice shall not be liable for any incidental or consequential damages including, without limitation, injury to persons or property or loss of use. Some states do not allow the exclusion or limitation of incidental or consequential damages so the above limitation or exclusion may not apply to you. [. . . ]