User manual ELECTRO-VOICE DL12X

[. . . ] All directional information was measured at 20 feet. Figure 8 illustrates the horizontal and vertical polar responses. Figure 6 shows the horizontal and vertical beamwidths. Beamwidth is the angle at which the horizontal and vertical polar responses have decreased in level by 6 dB when compared to the axial frequency response. [. . . ] In such designs, the vent, or port, actually provides the lowest octave of output. The vent is driven to full acoustic output by a relatively small motion of the speaker cone itself, acting through the air contained within the enclosure. The excursion of the DL15X at these frequencies is much reduced compared to sealed or open-back enclosures, directly reducing harmonic distortion and the possibility of speaker bottoming. See Figure 11 for maximum potential output over the frequency range. Vented-enclosure recommendations follow, some incorporating low-frequency equalization. Thiele-Small parameters are provided so designers can tailor the response to suit their needs. Normally Tuned Enclosures See Figures 9A and 9B. The 6-cubic-foot enclosure is tuned to 35 Hz and has an extended response to below 40 Hz. The 4-foot enclosure has a response that "bumps up" from 60 to 110 Hz but has less extended low-bass output. 7, "DL Series Woofers--Plans for Recommended Vented Enclosures and Small- and Large-Signal Performance for These Enclosures, " is available from ElectroVoice at no charge. A wide variety of enclosure sizes and degree of low-frequency extension is described in this literature. Since acoustic output is also falling rapidly, there is no utility in driving the system with signals much below tuning frequency. While such signals may be in the program material, they are often extraneous, such as a dropped microphone. The stepdown equalization described in the Step-Down Operation section provides the required protection. If step-down equalization is not used, the Electro-Voice EX-24, XEQ-2 and XEQ-3 electronic crossover/equalizers can also provide subpassband protection. The 3-dB-down points are 30 Hz (EX-24 and XEQ-2) and 16 Hz or 32 Hz (XEQ-3). Other high-pass filters are available, and onethird-octave equalizers can also be effective at providing the required protection. USE IN MULTIPLES Cone loudspeakers may be stacked for greater acoustic output and a narrower beamwidth. (It is assumed that all cones are operating in unison or in phase. ) At relatively low frequencies (below about 150 Hz for typical enclosures) stacking produces additional acoustic output without altering dispersion. When a common signal is applied, a 6dB increase in maximum acoustic output is possible. This increase occurs because the cones "mutually couple, " acting as one cone with twice the area (therefore, twice the efficiency) and twice the power-handling capacity of a single cone. [. . . ] Obtaining Warranty Service: To obtain warranty service, a customer must deliver the product, prepaid, to Electro-Voice or any of its authorized service representatives together with proof of purchase of the product in the form of a bill of sale or receipted invoice. A list of authorized service representatives is available from Electro-Voice at 600 Cecil Street, Buchanan, MI 49107 (616/695-6831 or 800/ 234-6831). Incidental and Consequential Damages Excluded: Product repair or replacement and return to the customer are the only remedies provided to the customer. ElectroVoice shall not be liable for any incidental or consequential damages including, without limitation, injury to persons or property or loss of use. [. . . ]