User manual ELECTRO-VOICE DMC-2181

[. . . ] The heart of the Eliminator iiTM `s high performance design is the combination of a high-excursion low-frequency suspension system with Electro-Voice's unique Ring-Mode Decoupling. All loudspeaker drivers exhibit mechanical resonance modes that add their own time-domain or ringing-mode colorations. The Eliminator iiTM uses RMD to control several fundamental ringing modes. The result is substantially improved vocal range intelligibility and system "openness". [. . . ] Two 15 inch drivers provide very high output at the lower frequencies. When extended high output low-frequency operation is required, performance can be further enhanced by biamping the Eliminator iiTM with the Eliminator iTM Sub. Vented enclosures offer excellent power handling and low distortion in the lowest octave of rate operation. However, it is always advisable to filter material below enclosure tuning to further improve system output and headroom. The Eliminator ii TM should be high-pass filtered to reduce subsonic material below 40 Hz. Architects' and Engineers' Specifications The loudspeaker system shall consist of two 38. 1-cm (15 inch) low-frequency tranducers in a vented enclosure. The high-frequency section shall be a compression driver with a pure titanium diaphragm coupled to a 1-inch throat diameter to a constant-directivity horn having a horizontal included angle (referenced to ­6 dB) of 60° and a vertical included angle of 40° nominal. The loudspeaker shall have a rated frequency response of 50 Hz to 20 Hz ± 3 dB and a long-term rated average power handling of 600 watts (EIA RS-426A). The system sensitivity shall be 100 dB when measured in an anechoic environment with a 1-watt input with a calibrated measurement microphone located 1 meter from the system axis. The system shall have parallel Neutrik® NL4MP connectors. Specifications: Frequency Response, Measured at 10 feet on axis (normalized to 1 watt/ 1 meter): . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . First, we use a random-noise input signal because it contains many frequencies simultaneously, just like real voice or instrument program. Second, our signal contains more energy at extremely high and low frequencies than typical actual program, adding an extra measure of reliability. Third, the test signal includes not only the overall "long term average" or "continuous" level ­ which our ears interpret as loudness ­ but also short-duration peaks which are many times higher than the average, just like actual program. The instantaneous peaks test mechanical reliability (cone and diaphragm excursion). Note that the sine-wave test signals sometimes used have a much less demanding peak value relative to their average level. In actual use, longterm average levels exist from several seconds on up, but we apply the long-term average for several hours, adding another extra measure of reliability. Specifically, the Eliminator ii TM is designed to withstand the power test described in the ANSI/EIA RS-426-A 1980. To obtain the spectrum, the output of a white-noise generator (white noise is a particular type of random noise with equal energy per bandwidth in Hz) is fed to a shaping filter with 6-dB-per-octave slopes below 40 Hz and above 318 Hz. When measured with the usual constantpercentage bandwidth analyzer (one-third-octave), this shaping filter produces a spectrum whose 3-dB-down points are at 100 Hz and 1, 200 Hz with a 3-dB-per-octave slope above 1, 200 Hz. Amplifier Recommendations The power-handling rating of the Eliminator iiTM is 600-watts continuous. The specific tests used employ a crest factor (ratio of peak energy to continuous energy) of at least 6 dB. [. . . ] The specific tests used employ a crest factor (ratio of peak energy to continuous energy) of at least 6 dB. During extended testing, the Eliminator iiTM is routinely subjected to peak levels far in excess of its continuous rating of 600 watts. Many amplifier designs are capable of producing peak power levels in excess of their ratings as well, so exact "pairing" of loudspeaker rating and amplifier ratings is not necessary. Amplifier continuous ratings of 300 watts to 600 watts into 4 ohms are suggested. Figure 1. [. . . ]