User manual ELECTRO-VOICE CWR-1 INSTALLATION

[. . . ] A cable entrance is provided on the bottom side Voice-Coil Diameter: 5. 1 cm (2. 0 in. ) Magnet Weight: 0. 93 kg (2. 1 Ib) with plates Magnet Material: Alnico V Dimensions, Height: 25. 4 cm (10. 0 in. ) Width: 16. 4 cm (6. 4 in. ) Depth: 1 1. 3 cm (4. 4 in. ) Net Weight: 4. 0 kg (8. 8 Ib) Shipping Weight: 4. 5 kg (10. 0 Ib) DESCRIPTION The University Sound MM2TC is aconservatively rated 25-watt "submergence-proof'' speaker designed for wall, ceiling, or bulkhead mounting. The driver employs a diaphragm with a phenolic impregnated linen-base and 2. 0-inch voice coil with "W" shaped Alnico V magnet structure. Provisions are made in the housing for installation of a matching transformer such as the University Sound model 5030 (30 W). [. . . ] Provisions are made in the housing for installation of a matching transformer such as the University Sound model 5030 (30 W). The voice-coil/diaphragm assembly is protected by a special anit-fungicide treatment and is easily accessible for cleaning by removal of the die-cast reflector on the front of the speaker. The MM2TC is self-draining and designed to withstand fungus, dust, salt spray, live steam, and gases. It is built to penetrate high noise levels in boiler rooms, mines, railroads, etc. _- DIRECTIONAL PERFORMANCE The directional characteristics of the MM2TC were measured by running a set of polar responses in University's large anechoic chamber. The test signal was %-octaveband-limited pseudo-random pink noise centered at the IS0 standard frequencies indicated in Figure 1 Additional typical data is provided in Figure 2 which indicates 6-dB-down beamwidth versus frequency for an MM2TC. The bell, reflector, and weatherproof transformer housing shall be die-cast aluminum and designed so that reflector can be removed for easy accessibility and cleaning of diaphragm. Voice-coilldiaphragm assembly shall be protected by special antifungicide treatment. Transformer housing shall be provided for installation of line-matching transformer not to exceed 5. 8 cm (2. 25 in. ), by 5. 8 cm (2. 25 in. ), by 7. 0 cm (2. 75 in. ). Two 13/32-inch diameter holes shall be provided for mounting purposes. FAX 8181367-5292 Applications and technical information for University Sound products: University Sound, Inc. , Technical Coordinator, Phone 8181362-951 6, FAX 81813673292, Specifications subject to change without notice. ARCHITECTS' AND ENGINEERS' SPECIFICATIONS The loudspeaker shall be integral driver and submergence-proof speaker with a phenolic impregnated linen-base diaphragm and rugged two-inch voice coil. The axial frequency response will extend from 800 to 5, 000 Hz and the horn shall exhibit a low-frequency cutoff of 600 Hz. Sound pressure level will be 104 dB (1 Wl1 M) with an 800 to 5, 000 Hz pink noise signal applied. Dispersion shall be 82O at 2 kHz. I BASIC GUIDELINES FOR THE USE OF HORNS AND DRIVERS WITHIN A SOUND SYSTEM. DESIGNING FOR INTELLIGIBILITY AND ADEQUATE SPL The Basic Idea Many sound systems would have better performance if the following basic principles are kept in mind Speakers with the appropriatecoverage patterns should bechosen, aimed and powered to achievea uniform direct field in the highly absorbtiveaudience, with no sound aimed at the reflective wall and ceiling surfaces Where multiple speakers are required in order to achieve a uniformdirect field, their coverage patterns should beonlyslightlyoverlapped, so that each section of the audience is covered by a single speaker To the extent this ideal is achieved reverberation is minimized and intelligibility is maximized The following materialexplains these concepts in more detail and illustrates two design approaches What is Reverberation?Reverberationis the persistence of sound within an enclosure, such asa room, after the original sound has ceased Reverberationmay also be considered as aseries of multiple echoes so closely spaced in time that they merge into a single continuous sound These echoes decrease in level with successive reflections, and eventually are completely absorbed by the room Non-Reverberant Environments An open, outdoor space is consideredto be a non-reverberant environment, as virtually all sound escapes the area without reflection. Variations in Level Due to Distance for Non-Reverberant Environments In non-reverberant environments, such as outdoors, sound pressure level will be reduced by half (6 dB) every time the distance form thespeaker is doubled (this is called the inverse-square law). Figure A shows the dB losses to be expected as distance from the speaker is increased from the one-meter (3 28-foot) measuring distance typically used in SPL specifications. Reverberant Environments Wheresound is reflectedfrom wallsand other surfaces, thereisapoint beyond which the "reverberant field" dominates and the sound pressure level is higher and more constant than predicted by using the inverse-square law alone Variations in Level Due to Distance for Reverberant Environments The reverberantfield will begin todominatetypicallyatdistancesof 10to30 feet This distance is greatest for the least reverberant rooms and speakers with narrow beamwidthangles The frequency and beamwidth speckations provided by the datasheet are still required to obtain satisfactory distribution of the direct sound (or direct field) from the loudspeaker(s) which still follows the inverse square law It is the direct signal that contributes to speech intelligibility This is why the sound system designer should seek a uniform directfield, with aslittle reverberantfieldas possible For example, consider a single speaker with awide beamwidth angle used to cover a long, narrow reverberantroom The direct field will be so far below the reverberant field at the backof the room that speech will probably be unintelligible Calculating Variations in Level Due to Changes in Electrical Power Each time the power delivered to the speaker is reduced by one-half, a level dropof3dBoccurs Thenomographof FigureBshowsthethechangein dB to be expected as the power varies from the one-watt input typically used in SPL specifications Power Handling The power rating of a speaker must be known to determine whethera design is capable of meeting the sound pressure level requirementsof the system The power rating combined with the sensitivity will enable a system designer to calculatethe maximum sound pressure level attainableat a given distance DISTANCE FROM SPEAKE:IH; 4 CHANGE IN (dB) M a $ lmm M : : FIGURE A Level Variation With Distance FIGURE B Level Variation With Power 3+m f25 M Powering to Achieve Both Average and Peak SPL to The average power that must be delivered to the speaker@) achieve the desired average SPL can be determined from the previously presented material on speaker sensitivity, level variation with distance and level variation with power. Enough additional power must be available to reproduce without distortion the short-term peaks that exist in voice and music program. [. . . ] Figure A shows the dB losses to be expected as distance from the speaker is increased from the one-meter (3 28-foot) measuring distance typically used in SPL specifications. Reverberant Environments Wheresound is reflectedfrom wallsand other surfaces, thereisapoint beyond which the "reverberant field" dominates and the sound pressure level is higher and more constant than predicted by using the inverse-square law alone Variations in Level Due to Distance for Reverberant Environments The reverberantfield will begin todominatetypicallyatdistancesof 10to30 feet This distance is greatest for the least reverberant rooms and speakers with narrow beamwidthangles The frequency and beamwidth speckations provided by the datasheet are still required to obtain satisfactory distribution of the direct sound (or direct field) from the loudspeaker(s) which still follows the inverse square law It is the direct signal that contributes to speech intelligibility This is why the sound system designer should seek a uniform directfield, with aslittle reverberantfieldas possible For example, consider a single speaker with awide beamwidth angle used to cover a long, narrow reverberantroom The direct field will be so far below the reverberant field at the backof the room that speech will probably be unintelligible Calculating Variations in Level Due to Changes in Electrical Power Each time the power delivered to the speaker is reduced by one-half, a level dropof3dBoccurs Thenomographof FigureBshowsthethechangein dB to be expected as the power varies from the one-watt input typically used in SPL specifications Power Handling The power rating of a speaker must be known to determine whethera design is capable of meeting the sound pressure level requirementsof the system The power rating combined with the sensitivity will enable a system designer to calculatethe maximum sound pressure level attainableat a given distance DISTANCE FROM SPEAKE:IH; 4 CHANGE IN (dB) M a $ lmm M : : FIGURE A Level Variation With Distance FIGURE B Level Variation With Power 3+m f25 M Powering to Achieve Both Average and Peak SPL to The average power that must be delivered to the speaker@) achieve the desired average SPL can be determined from the previously presented material on speaker sensitivity, level variation with distance and level variation with power. Enough additional power must be available to reproduce without distortion the short-term peaks that exist in voice and music program. [. . . ]