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Electro-Voice EVF/EVH User Manual 21
4.0 Preparing EVF and EVH Systems for Installation (cont’)
Figure 12:
An EVH hard foam waveguide contour
being removed for reorientation
4.5 Digital Signal Processing
4.51 Full-Range Systems in Passive Mode
For full-range systems in the passive mode, the internal crossover/equalizer network sends low frequen-
cies to the woofer and high frequencies to the compression-driver/waveguide combination. In addition,
the network tailors the frequency response and levels of each individual driver so that the overall frequen-
cy response of the loudspeaker is essentially flat over its design operating range.
Once a cluster of EVF and/or EVH systems is installed in a venue, a digital signal processor (DSP) will
typically be used to adjust the in-room frequency response, based on the specifics of the situation. In
addition, the DSP should be used to provide the high-pass filters recommended to protect EVF and EVH
systems against overdrive at frequencies below their operating range. Failure to do so could damage the
low-frequency drivers if fed high-level signals below the system’s operating range. Table 3 shows the
recommend high-pass filter frequencies for infrasonic protection of EVF and EVH systems. Different high-
pass filter frequencies are recommended for some fiberglass versions based on changes in operation
range due to the effects of having a sealed enclosure.
Table 3:
Recommended high-pass frequencies for infrasonic protection of EVF and EVH systems
Model(s) Recommended High-Pass Frequency (minimum)
EVF-1122/XX 65 Hz
EVF-1152/XX 45 Hz (55 Hz for Fiberglass Versions)
EVF-1121S 50 Hz (55 Hz for Fiberglass Versions)
EVF-1151S 35 Hz (45 Hz for Fiberglass Versions)
EVF-1181S 33 Hz
EVF-2121S 45 Hz
EVF-2151D 35 Hz
EVH-1152/XX 60 Hz