LH 7M
Loudspeaker
TM
Power Handling
SERIES
Continuous
Program
Peak
1,000W
2,000W
4,000W
1,200W
2,000W
1,000W
2,400W
800W
1,000W
2,400W
4,000W
2,000W
4,800W
1,600W
2,000W
Full Range
LHTM7M
Other LH series loudspeakers
LHTM1
LHTM2
LHTM3
LHTM4
LHTM5M
LHTM6M
Features
• Smooth frequency response characteristics
• 500 watt continuous rated woofer
• 150 watt continuous rated compression driver
• 60 degree x 40 degree Constant Directivity horn with 2" throat
• High power crossover components
• Neutrik Speakon® connectors with automatic switching bi-amp input
• Dual-angle cabinet design
• Recessed steel handles with comfortable round hand-grip
• Stand adapter for side-fill use
• 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-Head™ finish
600W
1,000W
500W
1,200W
400W
500W
Description
The Crest Audio LH™7M is a newly designed two-way stage monitor
comprised of two 12" high-power woofers, one 2" exit compression
driver coupled to a 60° x 40° constant directivity horn.
As with all LH™ full-range speakers, this unit can be driven in fullrange or bi-amp mode simply by plugging into the desired jack on the
input plate. The LH™7M cabinet has a dual-angle back for use in long
and short throw applications. This shape also greatly reduces the
build-up of internal standing waves. Standing waves are internal amplitude peaks that occur due to reflections within the cabinet at frequencies related to the internal dimensions of the cabinet. This ensures a
minimum of mid-bass and mid-range coloration of the reproduced
sound due standing waves within the cabinet. Additionally, a stand
mount adapter is included for easy side-fill applications.
The LH™7M is constructed of very high quality 3/4" 7-ply all-Poplar plywood, which is void-free, medium density, and warp-resistant.The LH™7M
cabinet is finished with Crest Audio’s durable black Hammer-Head polycoating. Polymer corners are also added to provide further protection to the
cabinet. A black powder-coated heavy-gauge metal grill covers the entire
front of the monitor to protect the drivers from unforeseen impacts.
Crest Audio’s protection circuit for mid and high frequency driver protection is included as a standard feature. The input signal is routed
through the protection circuit in both full-range and bi-amp modes of
operation. When high frequency drive level to the LH™7M exceeds
predetermined thresholds, the protection circuit is temporarily
engaged. This subtly decreases the signal level applies to high frequency driver so that it will not be damaged due to long term overpowering. Short duration transients will not be attenuated by the protection circuit and thus have the potential to damage the driver. The
protection circuit is realized through the use of a dynamically resistive
component in conjunction with a switched padding circuit.
An additional feature of the crossover is the use of a new switching
Neutrik Speakon® connector for the bi-amp input. It is no longer necessary to manually switch, or move jumpers to reconfigure the
crossover circuitry when bi-amping any of the LH series loudspeakers. This connector is wired 1+, 1- for the woofer, with 1+ being positive, and 2+, 2- for the high frequency driver, with 2+ being positive.
As with the full range inputs, simply insert your Speakon bi-amp plug
into the bi-amp input connector, and twist clockwise 1/8 turn. This simple action switches out the crossover, and simultaneously connects
the woofer and driver directly to the bi-amp speaker cable.
Specifications
TM
LH 7M Loudspeaker
Power Handling
Amplitude Response (1W 1m On-Axis)
dB SPL (re 20 Pa)
Crest Audio rates this unit’s system power
handling using a modified form of the AES
Standard 2-1984. 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 impact 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.
110
100
90
80
70
20
50
100
200
Figure 1
500
1k
Frequency (Hz)
2k
5k
10k
20k
2k
5k
10k
20k
Impedance
Frequency Response
This measurement is useful in determining how accurately a given unit reproduces an input signal. The frequency
response of the LH™7M (Figure 1) is
measured at a distance of 1-meter using a
1 watt (into the nominal impedance)
swept-sine input signal.
100
50
30
Z 20
( ) 10
5
3
2
1
20
Figure 2
50
100
200
500
1k
Frequency (Hz)
Specifications
TM
LH 7M Loudspeaker
LHTM7M Loudspeaker
frequency response
usable low frequency limit (-10 dB point)
58 Hz to 20 kHz (±3 dB)
47 Hz
power handling
Full Range: 1,000 W continuous 89.4 V RMS 2,000 W program 4,000 W peak
passive high freq: 150 W continuous 34.6 V RMS 300 W program 600 W peak
sound pressure level
Full Range
97.0 dB SPL, (2.83 V input)
high freq107 dB SPL, (2.83 V input)
maximum sound pressure level (1 meter)
radiation angle measured
transducer complement
box tuning frequency
Full Range
126.8 dB SPL continuous 132.8 dB SPL peak
High Freq
134.5 dB SPL continuous 140.5 dB SPL peak
90 degrees horizontal x 40 degrees vertical
Low Freq
1x 15" Woofer, vented basket
High Freq
2.0" Exit / 75 mm voice coil compression driver on a CD horn
Fbox
56 Hz
crossover frequency (internal passive)
Low Freq
High Freq - 1700 Hz
recommended minimum active crossover
Low Freq
High Freq - 1500 Hz at 12 dB/octave
time offset
Low Freq
0.00 ms
High Freq
0.60 ms
Full Range
Nominal 8.0Ω
Minimum 7.1Ω
High Freq
Nominal 8.0Ω
Minimum 6.8Ω
impedance Z
2x Neutrik Speakon

input connections
4 conductor input jacks
1x Neutrik Speakon 4
conductor biamp switching input jack
enclosure materials and finish
3/4" 7-ply premium, exterior grade, all-poplar, void-free plywood. Material conforms
to APA-1 specification. Finished in black, Hammer-Head poly-coating.
front
dimensions (H x W x D)
net weight
Architects’ & Engineers’ Specifications:
The loudspeaker system shall have an operating bandwidth of 59 Hz to 20 kHz. The nominal
output level shall be 97.0 dB when measured
at a distance of one meter with an input of one
watt. The nominal impedance shall be 8.0
ohms. The maximum continuous power han-
30.5" x 219.0" x 17.0"
775 mm x 483 mm x 445 mm
97 Lbs. (44.1 kg)
dling 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 60
degrees in the horizontal plane and 40 degrees
in the vertical plane. The outside dimensions
shall be 30.5 inches high by 19.0 inches wide by
17.0 inches deep. The weight shall be 97
pounds. The loudspeaker system shall be a
Crest Audio model LH™7M.
Crest Audio reserves the right to make improvements in manufacturing or design which may affect specifications.
8/22/01
v.1.5
*80304812*
Crest Audio Inc.
16-00 Pollitt Dr. Fair Lawn, NJ 07410
TEL: 201.909.8700 FAX: 201.909.8744
www.crestaudio.com