User manual ELECTRO-VOICE EVA

[. . . ] EVA Series User Manual EVA-2082S/906 EVA-2082S/920 EVA-2082S/126 EVA-2082S/1220 Electro-Voice® EVA Series User Manual Table of Contents Rigging-Safety Warning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. 0 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2. 0 Tool List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 3. 0 Designing an EVA Array . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 3. 1 Applications for which EVA Arrays are Most Appropriate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 3. 2 Typical Number of Arrays. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 3. 3 Determining EVA Array Configuration with EVADATM (EVA Design Assistant) Software . . . . . . . . . . . . . 8 3. 4 Other Design Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 3. 41 Dealing with the Relatively High Low-Frequency Variation of Short Arrays. . . . . . . . . . . . . . . . . . 14 3. 42 A Five-Module Array Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 3. 43 An Eight-Module Array Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [. . . ] This provides a more uniform spectral balance front to back, which may be preferred to the performance shown in Figure 4. Figure 8: A three-module EVA example of Figure 4, modified to improve the front-to-back "tracking" of all three predicted frequencies 14 Electro-Voice® EVA Series User Manual 3. 0 Designing an EVA Array (cont') 3. 42 A Five-Module Array Example Figure 9 shows another, five-module array in an 80-ft-deep venue with the front row five ft from the array and whose floor begins to rise about halfway back. The three frequencies not only track very well but nearly all of the venue is within ±3 dB front to back. This desirable situation is helped by not only the 3-dB attenuation of the top module but also by the array being longer than the three-module examples above (4. 4 ft versus 7. 3 ft). Figure 9: A five-module EVA example whose three predicted frequencies not only track well front-to-back, but also fall mostly within the desired ±3 dB Electro-Voice® EVA Series User Manual 15 3. 0 Designing an EVA Array (cont') 3. 43 An Eight-Module Example Figure 10 shows an eight-module array in a large theater with two balconies. Note that this array cannot be driven from one amplifier channel because only one of the modules uses the optional EVA-AM attenuation module. (An eight-module EVA array can be driven from an amplifier capable of driving a 2. 3-ohm nominal impedance if two of the modules have attenuation modules installed. A solution is to use two amplifier channels, one for the top four modules and one for the bottom four. In order to preserve the predicted array coverage, be certain that the voltage gains of both channels are the same. ) Nearly all of the 100-ft-deep main floor is covered within the optimum ±3 dB at all three predicted frequencies. The same uniformity applies to the first balcony (108 ft at the rear wall) although the average level drops by about 3 dB. The upper balcony (also 108 ft at its rear wall) shows a bit wider variation and less uniform tracking of the three predicted frequencies. However, the total variation in the upper balcony is still an acceptable ±4 dB. Figure 10: A eight-module EVA example in a large theater with two balconies (see text above for more details) 16 Electro-Voice® EVA Series User Manual 4. 0 Preparing EVA Modules for Installation 4. 1 Recommended Preflight Procedures For any installed sound system, certain checks made at the installer's place of business can prevent expensive on-site delays. A short-list follows, and sets the stage for proper array performance: 1. Check the overall condition of the loudspeakers. Check for continuity at the loudspeaker inputs. It is a good idea, once on site and the loudspeakers are connected, to check again for continuity at the power-amplifier end. 4. 2 Module Configuration After the EVADA software has been used to design an appropriate array, the high-frequency (HF) shading or use of the optional attenuation modules should be noted. In this way, these settings and options can be configured on the systems as they are rigged together and suspended. (The shading adjustments and installation of attenuation modules can be completed at the installer's shop but then care must be taken to see that the EVA modules are properly identified to avoid misassembly of the array in the field. ) Figure 11 shows an EVA HF shading switch card. This card comes pre-inserted in the "Center = Both @ 0 dB" position, indicating no shading of either HF element. Figure 11a: EVA input panel as supplied, with the high-frequency (HF) shading switch card in its central, 0 dB position Figure 11b: EVA input panel, with the switch card inserted to shade the lower HF element 3 dB Figure 11c: EVA input panel, with the switch card inserted to shade the upper HF element 3 dB Electro-Voice® EVA Series User Manual 17 4. 0 Preparing EVA Modules for Installation (cont') To attenuate the top HF element, remove the switch card by drawing it toward you using the central finger hole. (The switch can also be removed with the end of a flat-blade screwdriver, by placing the blade end in the switch hole and using the adjacent edge of the input panel as a fulcrum. To facilitate this operation, there is a small recess in the edge of the input panel adjacent to the hole in switch card. ) Reinsert the switch card one step higher to shade the upper HF element by 3 dB. Reinsert the switch card one step lower to shade the lower HF element. Some array designs will also use one or more of the optional EVA-AM attenuation modules. These attach to the inside of the input-panel assembly using the following steps: 1. [. . . ] Damaged structural supports should be replaced or repaired and recertified by a professional engineer. Never exceed the limitations or maximum recommended load for the supports. Miscellaneous Mechanical Components: Prior to each use, inspect all mechanical components (chain, wire ropes, slings, shackles, hooks, fittings, ratchet straps, etc. ) for any cracks, deformation, broken welds, slipping crimps, fraying, abrasion, knots, corrosion, chemical damage, loose screws, missing or damaged components that could reduce the maximum strength specified by the component manufacturer. Replace any damaged mechanical components immediately. [. . . ]