Electro-Voice 30W User's Manual
Contents
1. D C Resistance 4 ohms ENGINEERING DATA MODEL 30W Power Handling Capacity RMS 60 watts Pulsed 150 watts See Figure 6 Conversion Efficiency 10 EIA Sensitivity Rating 54 dB Recommended Crossover 100 Hz Voice Coil Diameter 2 inches Magnet Dimensions Net Weight Baffle Opening Mounting ENCLOSURE DESIGN 9 lb 4 oz ceramic 2954 dia 13 13 32 depth behind wall 34 pounds 28 inches 6 3 8 holes equally spaced on 28 7 8 circle As is the case with virtually any speaker the enclosure determines the actual performance of the 30W There are a number of enclosure approaches suitable for the 30W each with certain special advantages a as upon the intended use of the speaker All recommended enclosures are sealed acoustic sus pension types Ported enclosures bass reflex are neither necessary nor desirable for the 30W Many factors can be varied to establish desired performance 1 Enclosure volume 2 Damping material 3 System environment 4 Mass loading ENCLOSURE VOLUME Figure 1 shows the variation of speaker resonance as the enclosure volume changes Be cause it is the response curve which is of interest rather than simply speaker resonance Figure 2 shows respresent ative response curves under anechoic or free field conditions Enclosure volumes of 22 50 and 300 cubic feet yield speaker resonances of 40 30 and 20 Hz respectively As the enclosure gets smaller and t2. Electro Voice l 4 1 uy H a a M i DESCRIPTION The Electro Voice Model 30W woofer represents a dramatic development in the art of bass speaker design Previously unattainable low frequency performance results from the combination of a massive magnet structure heavy duty edgewise wound copper voice coil and a rigid polystyrene foam cone A one piece diecast aluminum frame assures permanent component alignment while minimizing unit weight As a result the nine pound four ounce ceramic magnet in a twenty three pound magnetic circuit accounts for over two thirds of the total unit weight Reduced ear sensitivity in the low frequency range re quires high acoustic power to fully recreate the exciting and awe inspiring qualities of instruments such as the pipe organ and bass drum Because radiation resistance of a speaker at low frequencies is proportional to the cone radiating area acoustic power output of a smaller woofer is far less for a given excursion Even an excursion of one inch peak to peak with a typical twelve inch woofer delivers less than one acoustic watt at 40 Hz The 30W with a cone area of more than 500 square inches provides the needed tremendous increase in radiation resistance and permits levels of performance in the extreme bass range never before achieved Even at full power input cone motion is within the linear range SPECIFICATIONS Resonance 15 Hz 3 Hz Impedance Nominal 8 ohms Minimum 5 ohms
3. able to mass loading ENCLOSURE CONSTRUCTION Because any cabinet wall vibration is out of phase with the woofer cone panel vibrations will cancel a portion of the woofer output A concrete block enclosure is ideal but far from practical One inch plywood walls liberally braced with 2x4 sections is a good compromise method of reducing panel vibration with manageable weight cost and ease of construction Spacing of the 2x4 bracing on any panel should not exceed 24 inches in one direction Sixteen inch spacing provides a more rigid panel and is more convenient to lay out because most tape measures have sixteen inch centers indicated for all stud spacing All joints should be secured with a good grade of wood glue and coated nails except for removable access panels These should be secured with No 8 x 2 woodscrews Removable panels may be sealed with a closed cell foam tape such as that used for weather stripping or with non drying caulking compound Unlike most enclosures there is no need to line the interior walls of the cabinet with fiberglass The purpose of such a lining is to absorb standing waves inside the cabinet However the low frequencies of standing waves in 30W cabinets are not affected by a fiberglass lining on the cabinet walls Adding fiberglass to the enclosure as mentioned earlier alters the response curve by lowering the system Q and also reduces the amplitude of standing waves inside the enclosure Mountin
4. ained in a smaller angle of radiation and the bass response will tend to rise In an extremely large space approximating free field a response curve which is somewhat underdamped may provide the most satisfying performance On the other hand close reflecting surfaces will tend to boost low frequency response making an overdamped rolled off free field curve more desirable This can be achieved through the use of a larger enclosure and or fiberglass damping MASS LOADING When enclosure volume is severely limited mass loading can be used to reduce the resonant frequency at a slight sacrifice of efficiency This principle is employed in the Patrician 800 system yielding a modest size enclosure with the 30W for home use The simplest method of mass loading involves increasing the air load on the front of the speaker by facing the speaker toward a rigid surface such as a wall Figure 3 As the speaker is brought closer to the wall the effective fee Le aE NOMINAL RESONANCE GRAY AREA INDICATES IN USE RESONANCE RANGE POSSIBLE WITH FREE AIR RESONANCE TOLERANCE ENCLOSURE VOLUME CU FT 10 15 20 23 y 40 50 60 70 80 90 100 RESONANCE Hz FIGURE 1 Enclosure Volume vs Resonance mass of air in front of the speaker increases lowering the resonant frequency Resonance can be lowered by as much as 25 with this technique However if cabinet space for a large enclosure is available the conventional approach is prefer
5. e made during installation While playing a source with substantial sound below 100 Hz such as an organ record reverse the connections at the woofer The connections with which bass response sounds WALL FIGURE 3 Phase Loaded Enclosures better is the proper connection If there seems to be no difference when the change is made then either con nection is proper This test is recommended because variations in speaker spacing and room acoustics may cause cancellation rather than reinforcement near the crossover frequency CUSTOMER SERVICE The 30W is packed to provide protection well in excess of shipping requirements of the Interstate Commerce Com mission If shipping damage does occur contact the carrier or the dealer from whom the unit was purchased and request inspection and instructions WARRANTY Limited Electro Voice high fidelity speakers speaker systems and accessories are guaranteed for five years from date of original purchase against malfunction due to defects in workmanship and materials If such malfunction occurs unit will be repaired or replaced at our option without charge for materials or labor if delivered prepaid to the proper Electro Voice service facility Unit will be returned prepaid Warranty does not cover finish or appearance items or malfunction due to abuse or operation at other than specified conditions Repair by other than Electro Voice or its authorized service agencies will void this gua
6. g the 30W in a wall will probably necessitate the removal of more than 30 inches of one stud Structural rigidity may be maintained through the use of a header and sill above and below the speaker as shown in Figure 4 For convenience the 30W may be secured to a one inch plywood mounting baffle which is then screwed to the wall studs and framing Before proceeding with the mounting of the 30W in this way however it is extremely advisable to consult with a competent architect or builder CONNECTIONS If the 30W is mounted in close proximity to the crossover and other components No 18 wire such as ordinary lamp cord is satisfactory If the 30W is mounted some distance from the other components No 16 or larger wire should be used to keep the resistance losses as low as possible Both Model X1835 crossover as used in the E V Patrician 800 and Model X1020 crossover are designed specifically WALL 2 MIN aoe ses Tega ea AT AO ZA 71 TN 10 30 40 50 60 80 100 200 nechoic volume Resonance anoa Damping at ETE TA CA 85 eomz 4aB Under Ce rze soe 20a Urar FIGURE 2 Response Curves for use with the 30W woofer Model X1835 should be used with the Patrician components the X1020 crossover allows the 30W to be added to an existing full range system The proper crossover frequency is 100 Hz In order to assure maximum bass response a simple phase reversing test should b
7. he speaker resonance goes up the speaker tends to become underdamped yielding a rise in the response curve at resonance An optimum response curve should be approximately 3 dB down at resonance The change in damping is a very broad effect with curves C and E representing an enclosure volume ratio of 13 to 1 By combining this effect with other variables which are controllable the response of the completed system can closely match requirements ACOUSTIC DAMPING MATERIAL An underdamped speaker can be compenstated for through the use of acoustic resistance added inside the enclosure Fiberglass builder s insulation available in batts and rolls for use between joists and studs is an inexpensive and effective damping material Any paper or foil backing should be removed before inserting the fiberglass in the enclosure Filling the enclosure until the fiberglass is slightly com pressed will reduce the resonant frequency up to 10 as well as slightly increasing the damping SYSTEM ENVIRONMENT The space in which the speaker is used can affect its performance as much as any other factor involved If the speaker is placed in an extremely large area away from reflecting surfaces its output will tend to be the same as anechoic or free field conditions If a speaker is placed against a solid wall the junction of two walls or in a corner formed by three walls 4 space space and 1 8 space conditions the low frequency energy is cont
8. rantee POWER INPUT WATTS AMS DURING ON TIME For correct shipping address instructions on return of Electro Voice products for repair and locations of authorized service agencies please write Service Depart ment Electro Voice Inc 600 Cecil Street Buchanan Michigan 49107 Phone 616 695 6831 FIGURE 5 Power Input vs Duty Factor Electro Voice also maintains complete facilities for non warranty service of E V products Specifications subject to change without notice HEADER STUD i Part No 534541 421 a Gulton ouav ELECTRO VOICE Inc 600 CECIL ST BUCHANAN MICH 49107 MANUFACTURING PLANTS AT E BUCHANAN MICH E NEWPORT TENN E SEVIERVILLE TENN E GANANOQUE ONT E LITHO IN U S A
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