User manual CREST AUDIO LH3 LOUDSPEAKER SPECIFICATIONS

[. . . ] LH 3 Loudspeaker TM SERIES Power Handling Full Range Continuous Program Peak LHTM3 LHTM1 LHTM2 LHTM4 LHTM5M LHTM6M LHTM7M 500W 600W 1, 000W 1, 200W 400W 500W 1, 000W 1, 000W 1, 200W 2, 000W 2, 400W 800W 1, 000W 2, 000W 2, 000W 2, 400W 4, 000W 4, 800W 1, 600W 2, 000W 4, 000W Other LH series loudspeakers Features · Smooth frequency response characteristics · 500 Watt continuous rated woofer · 140 Watt continuous rated mid-range compression driver · 90 degree x 40 degree constant directivity horn with 2" throat · High power crossover components · Neutrik Speakon® input connectors, with automatic biamp switching · 15 degree trapezoidal cabinet design · Recessed steel handles with comfortable round handgrip · Heavy gauge metal grill with black, powder-coat finish · High-impact resistant polypropylene cabinet corners · Rugged stand adapter · Exterior grade 3/4", 7-ply all poplar APA-1 plywood · Scuff and weather resistant, black Hammer-HeadTM finish Description The Crest Audio LHTM3 is a newly designed, three-way speaker system comprised of one 15" high-power woofer, one 8" heavy-duty mid-range, and a 2" exit compression driver coupled to a 90° x 40° constant directivity horn. As with all LHTM full-range speakers, this unit can be driven in full-range or biamp mode simply by plugging into the desired jack on the input plate. The LHTM3 has a trapezoidal shaped cabinet, rather than the more traditional rectangular shape. This allows cabinet arrays to be constructed more easily. [. . . ] Short duration transients will not be attenuated by the protection circuit and thus have the potential to damage the drivers. The protection circuit is realized through the use of a dynamically resistive component in conjunction with a switched padding circuit. An additional feature in the crossover circuitry is a mid-range contour switch. This switch allows a choice between flat (HIGH position) and mildly attenuated (NORMAL position) mid-range frequencies. The position of this switch is purely dependent on venue and personal sonic taste. As a suggestion, the NORMAL position is more suitable for live (highly reflective, long reverb time) venues. Whereas, the HIGH position is more suitable in venues where the reverb time is relatively short. This switch is located on the rear panel input plate and is actuated with a suitable tool such as a flat screwdriver tip, or door key. Specifications Power Handling 110 LH 3 Loudspeaker Amplitude Response (1W 1m On-Axis) dB SPL (re 20 Pa) TM There are many different approaches to power handling ratings. Crest Audio rates this unit's system power handling using a modified form of the AES Standard 21984. Utilizing audio band limited (20 Hz - 20 kHz) pink noise with peaks over four times the RMS level, this strenuous test signal assures the user that every portion of this system can withstand high inpact music. The test signal contains large amounts of low frequency energy, effectively simulating the frequency content of live music situations. High frequency test signals expose the speaker system to synthesized tones that may extend beyond audibility. This rating is contingent on having a minimum of 3 dB of amplifier headroom available so as to ensure that clipping does not occur. 100 90 80 70 20 50 100 200 Figure 1 100 50 30 Z 20 ( ) 10 5 3 2 1 20 500 1k Frequency (Hz) 2k 5k 10k 20k Lower Curve: Midrange Contour = Norm, Upper Curve: Midrange Contour = High Impedance Frequency Response This measurement is useful in determining how accurately a given unit reproduces an input signal. The frequency response of the LH3 (Figure 1) is measured at a distance of 1 meter using a 1 Watt (into the nominal impedance) sweptsine input signal. 50 100 200 Figure 2 360 300 Beamwidth (Degrees) 500 1k Frequency (Hz) 2k 5k 10k 20k Lower Curve: Midrange Contour = High, Upper Curve: Midrange Contour = Norm Beamwidth Directivity Beamwidth is derived from the -6 dB points from the polar plots which are measured in a whole space anechoic environment. Q and Directivity Index (Figures 3 & 4) are plotted for the on-axis measurement position. These are specifications that provide a reference to the coverage characteristics of the unit. These parameters provide insight for proper placement and installation in the chosen environment. 180 140 100 80 60 40 30 20 Horizontal Vertical 50 100 200 500 1k Frequency (Hz) 2k 5k 10k 20k Figure 3 100 Q & Directivity Index 20 Q 10 10 Di 1 20 50 100 200 Figure 4 500 1k Frequency (Hz) 2k 5k 10k 0 20k Specifications Horizontal Polars 0 30 o o LH 3 Loudspeaker TM 0 -30 o o 0 -30 o o 0 -30 o o 30 o 30 o 30 o -30 o 60 o -60 o 60 o -60 o 60 o -60 o 60 o -60 o 90 o -90 o 90 o -90 o 90 o -90 o 90 o -90 o 125 Hertz 250 Hertz 500 Hertz 1000 Hertz 0 30 o o 0 -30 o o 0 -30 o o 0 -30 o o 30 o 30 o 30 o -30 o 60 o -60 o 60 o -60 o 60 o -60 o 60 o -60 o 90 o -90 o 90 o -90 o 90 o -90 o 90 o -90 o 2000 Hertz 4000 Hertz 8000 Hertz 16000 Hertz Vertical Polars 90 o 90 60 o o 90 60 o o 90 60 o o 60 o 30 o 30 o 30 o 30 o 0 o 0 o 0 o 0 o -30 o -30 o -30 o -30 o 125 Hertz -60 -90 o o 250 Hertz -60 -90 o o 500 Hertz -60 -90 o o 1000 Hertz -60 -90 o o 90 o 90 60 o o 90 60 o o 90 60 o o 60 o 30 o 30 o 30 o 30 o 0 o 0 o 0 o 0 o -30 o -30 o -30 o -30 o 2000 Hertz -60 -90 o o 4000 Hertz -60 -90 o o 8000 Hertz -60 -90 o o 16000 Hertz -60 -90 o o Specifications LHTM3 Loudspeaker Frequency Response, 1 meter on-axis, swept-sine in anechoic environment: Usable Low Frequency Limit (-10 dB point): Power Handling: 53 Hz to 20 kHz (±3 dB) 40 Hz Full Range: 500 W continuous (63. 2 V RMS) 1, 000 W program 2, 000 W peak 150 W continuous (34. 6 V RMS) 300 W program 600 W peak LH 3 Loudspeaker TM Passive High Frequency Section: Sound Pressure Level, 1 Watt, 1 meter in anechoic environment: Mid / High Frequency Section: Maximum Sound Pressure Level (1 meter): Mid / High Frequency Section: Full Range: 97. 0 dB SPL, (2. 83 V input) 104 dB SPL, (2. 83 V input) Full Range: 126. 8 dB SPL continuous 132. 8 dB SPL peak 134. 5 dB SPL continuous 140. 5 dB SPL peak Radiation Angle measured at -6 dB point of polar response: Transducer Complement Low Frequency Section: Mid Frequency Section: High Frequency Section: Box Tuning Frequency: Crossover Frequency (internal passive): 90 degrees horizontal x 40 degrees vertical. exit / 75 mm voice coil compression driver on a CD horn Fbox: 36 Hz Low Frequency - Mid Frequency: 500 Hz Mid Frequency - High Frequency: 3, 700 Hz Recommended Active Crossover Frequency Region and Slope Mid Frequency - High Frequency: Time Offset: Impedance (Z): Passive MF/HF: High Frequency: 500 Hz at 18 dB/octave Low Frequency: 0. 00 ms Mid Frequency: -0. 30 ms High Frequency: 0. 60 ms Full Range: Nominal: 8. 0 Minimum: 6. 4 Nominal: 8. 0 Minimum: 8. 9 Nominal: 8. 0 Minimum: 6. 9 2x Neutrik Speakon® 4 conductor input jacks, 1x Neutrik Speakon® 4 conductor biamp switching input jack 3/4" 7-ply premium, exterior grade, all-poplar, void-free plywood. [. . . ] The maximum continuous power handling shall be 500 Watts, maximum program power of 1, 000 Watts and a peak power input of at least 2, 000 Watts, with a minimum amplifier headroom of 3 dB. The nominal radiation geometry shall be 90 degrees in the horizontal Crest Audio reserves the right to make improvements in manufacturing or design which may affect specifications. 8/22/01 v. 1. 5 *80304808* Crest Audio Inc. Fair Lawn, NJ 07410 TEL: 201. 909. 8700 FAX: 201. 909. 8744 www. crestaudio. com [. . . ]