Crest Audio LH4 LOUDSPEAKER User manual

Full Range
Other LH series loudspeakers
SERIES
Features Description
• Optimized low frequency response
• 1,200 Watt Continuous rated power
• Neutrik Speakon®input connectors
• Recessed steel handles with comfortable round handgrip
• Side and bottom feet for vertical or horizontal operation
• Integral pole stand socket
• Heavy-duty casters
• High-impact resistant polypropylene cabinet corners
• Heavy-gauge metal grill with black, powder-coated finish
• Exterior grade 3/4", 7-ply all poplar APA-1 plywood
• Scuff and weather resistant, black Hammer-Head™ finish
The Crest Audio LHTM4 is a low frequency reinforcement member of
the Crest LHTM series. The design consists of two 18" high power
woofers in an optimized vented enclosure. The woofers are connect-
ed independently to allow ease of connection to separate amplifiers
utilizing the same source. Alternatively, the woofers can be connect-
ed in parallel with an external adapter.
The LHTM4 is constructed of very high quality 3/4", 7-ply all-poplar ply-
wood, which is void-free, medium density, and warp-resistant. Side
feet for stacking enclosures horizontally are an additional feature. The
LHTM4 operated horizontally also provides a stable base for a pole-
mounted, multi-way application. An internal socket accepts a stand
pole for a mid/high speaker such as the Crest Audio LHTM1 or LHTM3.
Integral rear casters allow easy load-unload for quick venue setup.
The LHTM4 cabinet is finished with Crest Audio’s durable black
Hammer-Head poly-coating. Polymer corners are also added to pro-
vide further protection to the cabinet. A black, powder-coated, heavy-
gauge metal grill covers the entire front of the cabinet to protect the
low woofers from unforeseen impacts.
LHTM4
Loudspeaker
LHTM4
LHTM1
LHTM2
LHTM3
LHTM5M
LHTM6M
LHTM7M
1,200W
600W
1,000W
500W
400W
500W
1,000W
2,400W
1,200W
2,000W
1,000W
800W
1,000W
2,000W
4,800W
2,400W
4,000W
2,000W
1,600W
2,000W
4,000W
Power Handling Continuous Program Peak

Specifications LHTM4 Loudspeaker
Power Handling
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 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, effec-
tively 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.
Frequency Response
This measurement is useful in determin-
ing how accurately a given unit repro-
duces an input signal. The frequency
response of the LH4 (Figure 1) is meas-
ured at a distance of 1 meter using a 1
Watt (into the nominal impedance) swept-
sine input signal.
Directivity
The polar response of the LH4 is essen-
tially omni-directional at frequencies at
and below 200 Hertz.
20 50 100 200 500 1k 2k 5k 10k 20k
Frequency (Hz)
70
80
90
100
110
dB SPL (re20 Pa)
Amplitude R esponse (1W 1m O n-Axis)
Figure1
20 50 100 200 500 1k 2k 5k 10k 20k
Frequency (Hz)
1
2
3
5
10
20
30
50
100
Im pedance
Z
()
Figure2

Specifications LHTM4 Loudspeaker
Frequency Response, 1 meter on-axis,
swept-sine in anechoic environment:
Usable Low Frequency Limit (-10 dB point):
Power Handling:
Sound Pressure Level, 1 Watt, 1 meter in
anechoic environment:
Maximum Sound Pressure Level (1 meter):
Radiation Angle measured at -6 dB point
of polar response:
Transducer Complement
Low Frequency Section:
Box Tuning Frequency:
Recommended Active Crossover
Frequency Region and Slope
Mid Frequency - High Frequency:
Impedance (Z):
Input Connections:
Enclosure Materials & Finish:
Dimensions (H x W x D):
Net Weight:
LHTM4 Loudspeaker
45 Hz to 300 Hz (±3 dB)
31 Hz
Low Frequency Range: (speakers parallel, 4Ohms)
1,200 W continuous (69.3 V RMS)
2,400 W program
4,800 W peak
(speakers independent, 8 Ohms)
600 W continuous (69.3 V RMS)
1,200 W program
2,400 W peak
Low Frequency Range:
100.0 dB SPL, (2.00 V input)
Full Range:
129.8 dB SPL continuous
135.8 dB SPL peak
Essentially omni-directional
2x 18 in. woofer, vented basket
Fbox: 41 Hz
90 - 120 at 12 dB/octave
Nominal: 8.0 Ωeach
7.38 Ωparallel
Minimum: 8.0 Ωeach
3.69 Ωparallel
2x Neutrik Speakon®4 conductor input jacks, Upper woofer across 1+ & 1-, Lower
woofer across 2+ & 2-.
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.
47.0 in. x 23.25 in. x 26.375 in. 1,194 mm x 591 mm x 670 mm
144 Lbs. (65.5 kg)
Architects’ & Engineers’ Specifications:
The loudspeaker system shall have an operat-
ing bandwidth of 45 Hz to 300 Hz. The nominal
output level shall be 100 dB when measured at
a distance of one meter with an input of one
Watt. The nominal impedance shall be 8.0
Ohms independent, and 4.0 Ohms parallel.
The maximum continuous power handling
shall be 1,200 Watts, maximum program
power of 2,400 Watts and a peak power input
of at least 4,800 Watts, with a minimum ampli-
fier headroom of 3 dB.
The nominal radiation geometry shall be 180
degrees in the horizontal plane and 180 degrees
in the vertical plane. The outside dimensions
shall be 47 inches high by 23.25 inches wide by
26.375 inches deep. The weight shall be 144
pounds. The loudspeaker system shall be a
Crest Audio model LHTM4.

Crest Audio Inc.
16-00 Pollitt Dr. Fair Lawn, NJ 07410
TEL: [phone] FAX: [phone]
www.crestaudio.com
*80304809*
Crest Audio reserves the right to make improvements in manufacturing or design which may affect specifications.
8/22/01
v.1.5