is that 3dB of long-throw SPL and 1.5-2dB of side- fill level has been lost. A higher resolution data file is needed to provide a “real world realistic” simula- tion. Figure 5 shows the raw 2° polar data with the averaged 10° data superimposed. Also shown are floorplans from our 2° modeler, DCSO, the 5- degree AcoustaCADD and 10-degree EASE. By comparing the 2°, 5° and 10° resolution you can eas- ily see the apparent loss in direct-field SPL. This loss shows up as a series of “steps” along the length of the room and an artificially narrowed throw with less SPL in the corners than would be achieved in a real-world installation. Please keep this in mind when using simulation software.
Hanging EVI Systems:
For the EVI-12 and EVI-15 the physical mounting of the systems have been designed to be as easy as possible, with two simple options avail- able. By far, the easiest solution is to use the op- tional sturdy, cost effective EVI-12MB or EVI-15MB U-Brackets that mount to the 3/8-16 T-nut locations on the sidesoftheenclosure.Thesup- pliedforged-shoulder eyebolt must be used in the t-nut location on the lower back side of the system as a pull-up point (see figure 13). With this arrangement, the U-Bracket holds approximately 80% of the weight of the system, and the pull-up point pro- vides a convenient method of adjusting the aiming angle. The U-Brackets have easy-to-install bolt patterns and include three sets of OmniMount 100 bolt patterns. For most applications, this will be the preferred methodology as it is fast, aesthetically pleasing, flexible and inexpensive. However, this method will not work in all applications, so we have included a second set of T-nut locations on the top of the enclosure so that the hanging cables can be completely out of view from below (see Figure 14). The front pair of hanging points should carry ap- proximately 50 lbs of the enclosure’s weight, with the required pull-up point taking the balance of the weight (about 5 lb). The T-nut locations are intended to be used only with forged shoulder eyebolts with a minimum tensile strength of 350 kg (770 lb). The inexpensive EBK-1 kit includes three eyebolts, especially helpful when access to quality forged shoulder eyebolts is limited. Please keep in mind that the center of gravity is designed to be behind the main hanging points. This means that the back of the system will rotate as much as 50 degrees down, allowing easy aiming adjustment to virtually any angle.
Please note: the pull-up location on the lower section of the back panel of the enclosure MUST be used to hang the system in order to provide a safe, stable mounting system. The pull-up point pro- vides an additive safety, as it is capable of holding the speaker system with a safety factor of at least 5:1 in the unlikely event of a failure in the main load- bearing system.
For the EVI-28, the mounting holes are posi- tioned very near the center of gravity for easy aim- ing. The U-brackets may be rotated all the way around the back of the enclosure, allowing easy in- stallation and aiming. The maximum vertical angle that may be reached is approximately 35°, less if the loudspeaker is mounted flush against a ceiling. In this case, the enclosure may be rotated upwards by at least 15°, more than sufficient for nearly any application (see Figure 15). The brackets are sup- plied with friction washers that will prevent the en- closure from rotating over time, but to be abso- lutely certain, the installer should use a set screw in the threaded hole to fix the enclosure permanently in position.
The described hanging methods are rated for suspending only one speaker (with a minimum of an 8:1 safety factor). Hanging any additional weight from the speaker will exceed its strength rating and create an unsafe condition.
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 sys- tem with a single low-cost enclosure and still main- tain 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. Many auditoriums and theatres are much wider than a typical set of church pews, so Figure 6 shows a fairly standard auditorium floor plan and possible mounting locations. Any interference between the systems will be concentrated in the center aisle, where sound quality is not as critical. The EVI-12, EVI-15 and EVI-28 systems are also ideal for re- placing distributed arrays, providing much more uniform coverage at a lower cost. See Figure 7 for
