Electro-Voice PRO-12 User's Manual
Contents
1. direct field which still follows the inverse square law In installations where applicable it is good practice to make sure that the direct field is no more than 12 dB below the reverberant field if satisfactory intelligibility is to be obtained This condition is fulfilled if the listener is no more than four times critical distance from the loud speaker Level Variation with Power Each time the power de livered to the speaker is halved a drop of 3 dB occurs in any type of environment The nomograph of Figure 5 shows this effect i mani y SPL Rating 114 dB T 00 Hz Octave Band ji iej WHEN TWO SIGNALS ADD TO THE DIFFER BY LARGER READING 0 dB 3 00 dB 1 2 50 2 2 10 3 1 70 4 1 40 5 1 10 6 37 P 79 8 63 9 51 10 43 1 35 12 26 versie y ESN FG F FIGURE 4 Average Sine Wave Power Handling with Relation to Frequency One Hour art PEL OF FG EELEE FIGURE 2 Axial Frequency Response Shaded Area Octave Bands from 300 2400 Hz z0 9600 19 2 kHz FIGURE 3 Octave Band Polar Chart levels not normalized Level Variations due to Multiple Speakers The chart above indicates the total sound pressure level resulting from two loudspeakers aimed at the same point This chart greatly facilitates layout of systems employing multiple2. speakers POWER watts an s DISTANCE apse SPL Rating ik ns so 30 Pa mo 1o 105 100 s5 s j eo sE os 80 FIGURE 5 Nomographs WARRANTY The Electro Voice PRO 12 is guaranteed for two years against malfunction due to defects in workmanship and materials If malfunction from this cause occurs the unit will be repaired or replaced at our option without charge for materials or labor if delivered to Electro Voice or its service agency It will be returned prepaid Warranty does not cover finishes or failures due to abuse or operation at other than specified conditions Repair by other than Electro Voice or its authorized service agencies will void this guarantee a GUON comeany ELECTRO VOICE Inc 600 CECIL ST BUCHANAN MICH 49107 224 Part No 535307 Litho in U S A
3. 2 may be made by referring to the axial frequency response of Figure 2 as well as the octave band random noise polar response of Figure 3 From these figures the sound pressure level available at a distance of 4 feet with full power in may be determined for any octave band at any angle Level Variations with Distance Non Reverberant Environ ments In a non reverberant environment such as out of doors sound pressure level will drop 6 dB every time the distance from the speaker is doubled inverse square law The nomograph of Figure 5 shows the dB losses to be expected as distance from the PRO 12 is changed Level Variations with Distance Reverberant Environ ments Indoors Where sound is reflected from walls and TWO WAY SPEAKER O Ae m on 3 N z 5 z gt Fae m D other surfaces and the environment is reverberant there is a point the critical distance beyond which the reverberant field dominates and sound pressure is nearly constant This distance is typically ten to twenty five feet from the speaker and is shortest for the most reverberant rooms Because of the reverberant field the sound pressure level obtainable in a room is much higher and more constant than that predicted by the inverse square law alone However the information in Figures 2 and 3 is still necessary in order to obtain satisfactory dis tribution of the sound direct from the loudspeaker
4. 8 16 66 rae sane FIGURE 1 Dimensions INSTALLATION AND MOUNTING The PRO 12 was designed to provide a sound pressure level of approximately 100 dB when used in distributed systems installed in ceilings ranging from 20 to 30 feet in height Polar response has circular symmetry and sufficient beam width at 10 kHz so that speaker spacings nearly equal to ceiling height can be used with excellent uniformity of high frequency response even along diagonal lines between speaker centers ass response with the Model PRO 12 will be obtained by using the recommended six cubic foot enclosure volume A sealed box must be used for best bass results Cut an Il inch diameter circular hole in the mounting baffle Four 9 16 inch holes are provided on the periphery of the speaker frame for mounting Use No 12 inch wood screws or preferably drill four 44 inch spaced 90 degrees apart on an 11 9 16 inch circle and use four 3 16 inch carriage bolts 2 inches long with nuts and washers Tighten the carriage bolts just enough to compress the speaker gasket IMPORTANT If the speaker baffle becomes too thick i e in excess of inch undesirable peaks are generated in the on axis response between 1 5 and 4 kHz This is due in large part to diffraction from the tweeter off the edges of the hole in the baffle board Note an accessory predrilled mounting ring is available Order E V Model No P708 SYSTEM LAYOUT Accurate system layout with the PRO 1
5. ENGINEERING DATA DESCRIPTION The Electro Voice Model PRO 12 is a new two way speaker intended for professional sound reinforcement use The PRO 12 offers adequate power handling excellent dispersion and extremely smooth and wide frequency response for a reasonable price High efficiency is possible through the use of ceramic magnets in both tweeter and woofer construction Mounting the tweeter assembly closer to the woofer cone reduces reflections between cone and back of tweeter thus smoothing midrange response The design of the tweeter extends high frequency response past 16 000 Hz In distributed systems the broad smooth response and excellent dispersion give definite advantages in terms of gain before feedback and overall unequalized tonal quality SPECIFICATIONS Frequency Response in suggested enclosure Fig 2 60 16 000 Hz Nominal Resonance 47 Hz EIA Sensitivity 48 dB Crossover electrical 1 000 Hz Power Handling Program 60 watts Average 20 watts Figure 4 Sound Pressure Level 4 at 60 watts 1200 2400 Hz octave band random noise 114 dB Nominal Impedance 8 ohms Magnets Woofer 1 1b 6 oz ceramic Tweeter 4 15 oz ceramic Dispersion 120 nominal Figure 3 Size 124 diameter 6 deep Mounting Four 9 32 holes equally spaced on an 11 9 16 circle Figure 1 Baffle Opening 1l inches Net Weight 14 pounds MODEL PRO 12 9 32 OIA THRU amp HOLES EQUALLY SPACED ON 17
Download Pdf Manuals
Related Search