User manual ELECTRO-VOICE EVI-28 APPLICATION GUIDE

[. . . ] EVI-12, EVI-15 and EVI-28 Loudspeaker Systems Applications Guide Welcome to the world of Vari Intense® horn technology from Electro-Voice. This Applications Guide is not intended as a "very intense" description of installation procedures, but more as a partial description of applications and a discussion with the designer to help you understand this revolutionary technology and use the Electro-Voice Vari Intense® systems to install better-sounding systems and significantly reduce time and material costs. In a nutshell, here are the major advantages of the new EVI systems: · Rectangular coverage pattern. Traditional horns deliver an elliptical pattern to the floor. VI horns deliver a rectangular pattern, which helps to fill in the corners of the room. [. . . ] In contrast, the new VI systems have no problems with interference, and maintain very good tonality even far to the sides and to the back, outside the "equalSPL" pattern area. This effect is due to the precise matching of directivities in the midrange and treble, giving a consistent (although noticeably quieter) frequency response out to nearly 50 feet in width and 65­70 feet in length from the same 18-foot height and 0° aiming angle. This has the advantage of providing a much more uniform power response into the reverberant field, ensuring that the inevitable reflections (minimized by the VI concept) are consistent in tonal quality. EVI-28 Installation: The EVI-28 makes use of the same high-frequency horn as the EVI-12 and EVI-15, but includes a pair of high-power, high-efficiency 8" woofers in a very compact package. The system is provided with a 2, 000-Hz passive crossover featuring tweeter protection and a proprietary passive equalization circuit that provides frequency-shading, amplitude-shading and time delay to the two woofers. An Acoustic Lens Filter on the grille helps to eliminate spurious lobes and provides a degree of acoustic loading. These features heavily modify the polar response of the two woofers, providing an extremely uniform polar pattern with a shape that matches the VI horn's unique SPL profile. They also smooth the transition between woofers and the horn to minimize horizontal lobes, providing amazingly even coverage through the crossover point. This extends the VI characteristic down to 500 Hz in an extremely compact enclosure. The high-frequency horn in the EVI-28 is mounted tilted 15° back relative to the EVI-12 and EVI-15. Along with the polar steering in the woofer's crossover, this arranges the dispersion for long throws relative to the mounting height. The recommended operational vertical angle is minus 5°from the top surface of the enclosure to minus 45°, defining a maximum used vertical dispersion of 40°. The standard aiming of the system when it is mounted above a flat floor is with the top of the enclosure parallel to the floor. In this orientation, the system will provide even SPL over a floorplan that is approximately twice as wide as the mounting height, and five times as long. Tilting the enclosure down by approximately 10- to 15° relative to the slope of the floor will produce a floorplan the same as an EVI-12 or EVI-15. At the standard aiming, the 45° nearfield operational angle defines an approximate offset to the first useable row of one-half the height of the speaker system above the listening plane. In a typical installation, the top surface of the loudspeaker will point slightly above the head height of the furthest targeted seating or standing area. This will ensure the minimum amount of slap echo from the back wall. It is generally thought that a high-directivity horn will have greater intelligibility across a given pattern area than a lower-Q device, and this is true in most cases. Also true in most cases is that a standard horn pattern will not fill a typical floorplan, thus drastically reducing the effectiveness of the higher Q. In direct comparison, the VI horn pattern will fill a majority of floorplans with direct-field sound rather than relying on reverberant energy to "fill in the gaps" in overall sound quality and quantity. The Q of the VI systems are very consistent from 1, 000­20, 000 Hz, with a range of 10-18 (10-12. 5 dB) and an average Q of 13. 5 (11. 5dB) or consistent with the overall directivity of a 90o x 40o system. [. . . ] A Sampling of EVI Applications: Now that the technical details are covered, here are a few ideas on applications that the EVI systems will cover with far more uniform sound and lower overall cost than any conventional enclosure. The first and most obvious application is in a church or some other well-defined space that has a fairly tall ceiling, and proportions of roughly 2 x 3 (see Figure 1). In this application, the EVI systems can easily replace a central cluster or distributed system with a single low-cost enclosure and still maintain a more uniform sound distribution. Figure 2 shows a similar room, but with a somewhat longer throw, where the EVI systems also perform very well. [. . . ]