Architects' And Engineers' Specifications; Srm450 Block Diagram - Mackie SRM450 Brochure

SRM450

Architects' and Engineers' Specifications

The active two-way, full-range loudspeaker system
shall incorporate one 12-inch low-frequency (LF) trans-
ducer and a 1-inch exit/1.75-inch diaphragm compression
driver high-frequency (HF) transducer. The LF driver shall
be mounted in a vented polypropylene molded enclosure
tuned for optimum low-frequency response. The HF trans-
ducer shall be loaded on a multi-cell horn aperture and
mounted on a combination exponential and conical horn.
The system shall have a nominal coverage pattern of
90° (horizontal) x 40° (vertical). System frequency response
shall vary no more than ±3 dB from 55 Hz to 18 kHz
measured on axis. The loudspeaker shall incorporate a
Class G low-frequency amplifier capable of delivering 300
watts rms over a frequency range of 20 Hz-2000 Hz. The
system shall incorporate a Class AB 100 watt rms ampli-
fier specifically designed to power the HF driver over the
range of 1500 Hz-20 kHz. The amplifiers shall be mounted
on an aluminum heatsink, which shall be mounted on the
rear of the speaker system, and shall be convection cooled.

SRM450 Block Diagram

LOW CUT CONTOUR
J15
2
INPUT
3
1
2
THRU
3
SIGNAL THERMAL POWER
1
LED LED LEDS
THERMAL
SIGNAL
SENSE SWITCH
MUTE
MUTE
ON/OFF
LOW AC
CONTROL
VOLTS SENSE
+15VDC
TIMED
TURNOFF
OFF
SIGNAL
SENSE ON
SWEEPING
POWER
FILTER
SWITCH
FUSE
+
MID VDC
–
+
TOROIDAL POWER
LO VDC
TRANSFORMER
–
MACKIE
SRM450
BLOCK DIAGRAM
(#060322SEDF)
www.mackie.com
16220 Wood-Red Road NE, Woodinville, WA 98072 USA
800.898.3211, fax 425.487.4337, sales@mackie.com
UK
+44.1268.570.808, fax +44.1268.570.809, uk@mackie.com
Active Speaker System
THRESHOLD
HI-PASS
HI-FREQ
HI-FREQ
AMP
COMPRESSOR
PEAK
DETECTION
MUTE
40-120 Hz DELAY LO-PASS COMPRESSOR
176uS
LO-FREQ
AMP
+
HI VDC
THRESHOLD
THRESHOLD LPF
–
BASS CONTROL SERVO LOOP
Thermal protection shall be provided by a thermal
sensor mounted on the heatsink, which monitors the
heatsink temperature and triggers the thermal protection
circuit should the temperature exceed 158° F (70° C). The
Thermal LED shall light and the input signal to the ampli-
fiers shall be muted until the heatsink cools to a safe oper-
ating level, at which point the thermal protection circuit
auto-resets and normal operation resumes.
Overload protection for the LF driver shall be provided
by a dynamically variable high-pass filter, the corner fre-
quency of which shall slide from 40 Hz to 120 Hz as the LF
amplifier output approaches clipping. Additional protec-
tion shall be provided for both the LF and HF drivers by a
compressor circuit, which monitors the low-frequency and
high-frequency amplifier outputs and reduces the gain as
the amplifiers approach clipping.
The system shall include an XLR input connector, an
XLR loop-through signal connector, a level control capable
of providing up to 40 dB of gain to accommodate both
microphone and line-level signal levels, a sound contour
switch providing +3 dB of equalization at 100 Hz and 12 kHz,
a high-pass switch for filtering out frequencies below 75 Hz,
and a timed turn-off switch for self shut-down.
The loudspeaker enclosure shall have an asymmetrical
trapezoidal shape and shall incorporate 10 integrated
M10 fly points, two side handles, and a top relocation
handle. The enclosure shall be molded from polypropylene
material. The front of the loudspeaker shall be covered with
TWEET
a powder coated, weather-resistant perforated steel grille.
The active two-way full-range loudspeaker system shall
be a Mackie SRM450.
PEAK
LIGHT
LO-FREQUENCY
DRIVER
WOOF
SENSE
RESISTOR
Electronic files for this product available at:
www.mackie.com
This Specification Sheet
Owner/Operator's Manual
LOUD Technologies continually engages in research related to product improvement. New material,
production methods, and design refinements are introduced into existing products without notice as a
routine expression of that philosophy. For this reason, any current LOUD Technologies product may differ
in some respect from its published description, but will always equal or exceed the original design speci-
fications unless otherwise stated. ©1999-2004 LOUD Technologies Inc. All rights reserved. Mackie and
the "Running Man" figure are registered trademarks of LOUD Technologies Inc.
SRM450_SS.PDF
SRM450_OM.PDF
Part No. 091-221-00 Rev. B 09/04
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