User manual ELECTRO-VOICE 6001RB

[. . . ] 13 Gradient Arrays. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Characteristics of Gradient Arrays. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Advanced Gradient Drive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [. . . ] 1 / SEPTEMBER 18, 2009 Blue Red Green 40Hz 60Hz 90Hz Figure 20. Beamformed; trim height 65ft (~20m). Flown Center Subbass Line Arrays. Where staging and rigging considerations permit, a flown center stack of subwoofers can give excellent results. There is zero lobing, the horizontal coverage is essentially 360°, and the vertical coverage can be controlled well by beamforming. Figure 21 shows the coverage of a flown center cluster of 12 EV Xsub woofers in an arena venue. The woofers are hung in a straight line, an optimized set of beamforming delays are applied. As well, level shading has been applied. The result is a subbass coverage pattern that maintains constant tonal balance over the entire listening area and In this example, the delays have been applied in pairs. That is, each adjacent pair of woofers has a drive channel. This is more economical than having a separate drive and amplifier channel for each woofer. However, should a separate drive channel per woofer be available, even better coverage would be possible. 15 6001RB · A PRACTICAL Blue 40Hz Red 60Hz Green 90Hz GUIDE REV. Available patterns are similar to those of microphones: cardioid, hypercardioid (various types), and figure-8. Figure 24 and Figure 25 show four pattern options for the back-to-back Xsub pair from the example above. Figure 24. Right: Hypercardioid, ±135° nulls. Audience on the right. 18 6001RB · A PRACTICAL GUIDE REV. Left: Hypercardioid, ±120° nulls. When constructing a gradient pair, it is important to understand the role of element spacing. By "element spacing", we mean the distance between front and rear loudspeaker cones. Larger element spacing increases subbass output, but decreases maximum operating frequency. Smaller element spacing decreases output but increases maximum operating frequency. In our example, the element spacing is 62 inches (157 cm), which gives a maximum operating frequency of approximately 90 Hz. The pattern deteriorates rapidly above the high-frequency limit, as Figure 26 shows. Red Blue Green Circles 90Hz 100Hz 120Hz 6dB Figure 26. [. . . ] This principle leads to one of two signal path diagrams, depending on whether the subwoofers are driven as part of the main mix or from their own mix. Figure 36 shows the case in which the subwoofers are driven from the main mix. The subbass contour EQ is configured as a normal pre-crossover equalizer. Figure 37 shows the case in which the subwoofers are driven from a separate mix. [. . . ]