crest performance LQ15 LOUDSPEAKER User manual

Specifications LQTM15 Loudspeaker
Crest Audio Inc.
16-00 Pollitt Dr. Fair Lawn, NJ 07410 USA
TEL: [phone] FAX: [phone]
www.crestaudio.com
*80304798*
Crest Audio reserves the right to make improvements in manufacturing or design which may affect specifications.
8/21/01
v.1.5
Architects’ & Engineers’ Specifications:
The loudspeaker system shall have an
operating bandwidth of 64 Hz to 18 kHz.
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.
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 plane
and 45 degrees in the vertical plane.
The outside dimensions shall be 28.50
inches high by 21.25 inches wide by
17.25 inches deep. The weight shall be
56 pounds. The loudspeaker system
shall be a Crest model LQ 15.
Full Range
Other LQ series loudspeakers
SERIES
Features Description
• Quadratic Throat Geometry horn
• 1000 W program, 2000 W peak
• 15" cast frame 4" VC premium woofer
• Crest HFTM2 two-inch titanium compression driver
• DPS™ (Dynamic Protection System) tweeter protection
• Crossover EQ switch
• High power crossover components
• Top and bottom flying point inserts
• Multiple handles and 1-3/8" stand mount
• Available in White
The Crest LQ 15 is an injection-molded two-way speaker system,
engineered in the Crest tradition to provide superior performance
from a compact and durable package. The enclosure is made from
very high impact injection-molded polypropylene in a trapezoidal
shape with extensive ribbing and bracing. The grille is comprised of
perforated metal protected by a high quality vinyl coating process.
The two-way system is comprised of a 15" cast frame premium
woofer with a 4" voice coil and a water-resistant treated cone and dust
cap for superior environmental stability. Capable of over 500 W of con-
tinuous power handling (AES Std 2-1984). The high frequencies are
handled by a Crest HFTM2 two-inch titanium diaphragm compression
driver utilizing ferrofluid, coupled to a 1" Quadratic Throat Geometry
horn, integral molded to the cabinet. This horn provides outstanding
dispersion coupled with a well-controlled pattern and a smooth, even
response. Utilizing Quadratic Throat Horn™ technolog (US Patent
6,059,069) the horn has lower distortion than many popular CD horn
geometries. The Crest HF 2 driver utilizes the Radialinear Planar
Phase Correction System (US Patent 6,064,745) which provides
smoother and extended high frequency response.
Input connection to the system is made via two 1/4" phone jacks, and
two 4-pin Neutrik® jacks all connected in parallel are provided for signal
input and daisy chaining capability, while a 4-pin Neutrik switching jack
is provided for bi-amping flexibility while maintaining signal integrity.
The internal passive crossover features the DPS™ (Dynamic
Protection System) tweeter protection circuit, and an advanced topol-
ogy with high performance components, to provide high power han-
dling and reliability. The crossover provides driver roll-off and protec-
tion, as well as driver EQ for the woofer and horn. High-quality, reli-
able crossover components include polypropylene capacitors, and
extremely high current inductors and input connectors. The optimal
integration of the crossover with the selected drivers results in a
smooth frequency response from 64 Hz to 18 kHz. An EQ contour
switch is provided enabling the user to select one of two EQ settings.
One setting will yield a nominally flat frequency response, the other
reduces the upper mid range frequencies which can help in keeping
bright rooms from overloading, or to help achieve a mellower voicing
for those applications that prefer it, such as DJ use.
LQTM15
Loudspeaker
LQ15
LQ10
LQ12
500W
250W
500W
2,000W
1,000W
2,000W
Power Handling Continuous Peak
frequency
usable low frequency limit (-10 dB point)
power handling
sound pressure level
maximum sound pressure level (1 meter)
radiation angle measured
transducer complement
box tuning frequency
crossover frequency (internal passive)
recommended minimum active crossover
time offset
impedance (Z)
input connections
enclosure materials and finish
mounting provisions
dimensions (H x W x D)
net weight
64 Hz to 18 kHz (±3 dB)
48 Hz
Full range 500 W continuous 1,000 W program
High freq 60 W continuous 120 W program
Full range 100 dB SPL, (2.83 V input)
High freq 110 dB SPL, (2.83 V input)
Full range 126 dB SPL continuous 134 dB SPL peak
High freq 128 dB SPL continuous 134 dB SPL peak
90ohorizontal X 45overtical
Low freq 1x 15" woofer, vented
High freq 0.875 in. exit/51 mm voice Coil HF™2 compression driver on a CD horn
Fbox 58 Hz
Low freq High freq 1600 Hz
Low freq High freq 1600 Hz at 12 dB/octave
Low freq 0.00 ms High freq 0.00 ms horn spatially aligned
Full range nominal 8.0 Ωminimum 6.0 Ω
High freq nominal 8.0 Ωminimum 5.4 Ω
2x 1/4" phone jacks paralleled with
2x Neutrik®NL4 Speakon®for full range inputs.
1x Neutrik NL4S switching Speakon for bi-amp inputs.
Dark gray high-impact polypropylene 1/4" thick finished in molded textured finish
(8) 1/4"-20 threaded mounting points, 4 each top and bottom
Front 28.50 in. x 21.25 in. x 17.25 in. 724 mm x 540 mm x 438mm
Rear 26.75 in. x 11.63 in. x 17.25 in. 679 mm x 295 mm x 438 mm
56 lbs. (25.5 kg)
LQ15 Loudspeaker

Specifications LQTM15 Loudspeaker Specifications LQTM15 Loudspeaker
Horizontal Polars
Vertical Polars
-90o
-60o
-30o
0o
30o
60o
90o-90o
-60o
-30o
0o
30o
60o
90o-90o
-60o
-30o
0o
30o
60o
90o-90o
-60o
-30o
0o
30o
60o
90o
-90o
-60o
-30o
0o
30o
60o
90o-90o
-60o
-30o
0o
30o
60o
90o-90o
-60o
-30o
0o
30o
60o
90o-90o
-60o
-30o
0o
30o
60o
90o
125 Hertz 250 Hertz 500 Hertz 1000 Hertz
2000 Hertz 4000 Hertz 8000 Hertz 16000 Hertz
0o
30o
60o
90o
-30o
-60o
-90o
0o
30o
60o
90o
-30o
-60o
-90o
0o
30o
60o
90o
-30o
-60o
-90o
0o
30o
60o
90o
-30o
-60o
-90o
0o
30o
60o
90o
-30o
-60o
-90o
0o
30o
60o
90o
-30o
-60o
-90o
0o
30o
60o
90o
-30o
-60o
-90o
0o
30o
60o
90o
-30o
-60o
-90o
125 Hertz 250 Hertz 500 Hertz 1000 Hertz
2000 Hertz 4000 Hertz 8000 Hertz 16000 Hertz
Power Handling
There are many different approaches to
power handling ratings. Crest rates this
loudspeaker system’s power handling
using a full-range form of the AES
Standard 2-1984. Using audio band 20 Hz
to 20 kHz pink noise with peaks of four
times the RMS level, this strenuous test
signal assures the user that every portion
of this system can withstand high inpact
music. This rating is contingent upon hav-
ing a minimum of 3 dB of amplifier head-
room available.
Frequency Response
This measurement is useful in determin-
ing how accurately a given unit repro-
duces an input signal. The frequency
response of the Crest LQ 15 is measured
at a distance of 1-meter using a 1 Watt
(into the nominal impedance) swept-sine
input signal. As shown in figure 1, the
selected drivers in the Crest LQ 15 com-
bine to give a smooth frequency response
from 64 Hz to 18 kHz.
Directivity
Beamwidth is derived from the -6 dB
points from the polar plots (see figure 3)
which are measured in a whole space
anechoic environment. Q and Directivity
Index are plotted for the on-axis measure-
ment position. These are specifications
that provide a reference to the coverage
characteristics of the unit. These parame-
ters provide insight for proper placement
and installation in the chosen environ-
ment. The blending of the components of
the Crest LQ 15 exhibit a desirable
beamwidth and directivity (figure 3 and 4)
suitable for sound reinforcement applica-
tions.
20 50 100 200 500 1k 2k 5k 10k 20k
Frequency (Hz)
1
10
100
Q&DirectivityIndex
Q
Figure4
20
10
Di
0
20 50 100 200 500 1k 2k 5k 10k 20k
Frequency (Hz)
30
40
60
80
100
140
180
300
360
B eam w idth(Degrees)
B eam w idth
Vertical
Horizontal
Figure3
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
20 50 100 200 500 1k 2k 5k 10k 20k
Frequency (Hz)
60
70
80
90
100
110
dB SPL (re20 Pa)
Amplitude R esponse (1W 1m O n-Axis)
EQ
Normal
Sw itch P o sition
Figure1