Architects’ and Engineers’ Specifications

SPEAKER

SRM450 Active Speaker System

Architects’ and Engineers’ Specifications

SRM450

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

							THRESHOLD
			LOW CUT	CONTOUR
		J15				HI-PASS
						HI-PASS
INPUT	2					HI-FREQ	HI-FREQ	TWEET
	3						AMP	TWEET
	3						AMP
	1					COMPRESSOR
						COMPRESSOR
THRU	2
THRU	3
	3	SIGNAL		THERMAL	POWER
	1	SIGNAL		THERMAL	POWER
		LED		LED	LEDS
		SIGNAL	THERMAL					PEAK
		SIGNAL	THERMAL					DETECTION
		SENSE	SWITCH	MUTE	MUTE		MUTE	PEAK
			LOW AC	ON/OFF				LIGHT
	+15VDC		VOLTS SENSE	CONTROL
	+15VDC	TIMED
		TURNOFF
		OFF						LO-FREQUENCY
	SIGNAL					40-120 Hz DELAY LO-PASS COMPRESSOR		LO-FREQUENCY
	SENSE	ON				40-120 Hz DELAY LO-PASS COMPRESSOR		DRIVER
		POWER			SWEEPING	176uS
		POWER			SWEEPING		LO-FREQ
	FUSE	SWITCH			FILTER		LO-FREQ	WOOF
	FUSE	SWITCH			FILTER		AMP	WOOF

	+	+
	MID VDC	HI VDC	THRESHOLD	LPF	THRESHOLD
	–	–	THRESHOLD	LPF
					BASS CONTROL SERVO LOOP
TOROIDAL POWER	+
TRANSFORMER	–LO VDC				SENSE
					RESISTOR

MACKIE DESIGNS SRM450

BLOCK DIAGRAM (#060322SEDF)

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 accomodate 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 polyproylene material. The front of the loudspeaker shall be covered with a powder coated, weather-resistant perforated steel grille.

The active two-way full-range loudspeaker system shall be a Mackie Designs SRM450.

Electronic files for this product available at:

www.mackie.com

		This Specification Sheet			SRM450_SS.PDF
		Owner/Operator’s Manual			SRM450_OM.PDF
		CADD files			SRM450.DXF
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	tion methods, and design refinements are introduced into existing products without notice as a routine
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www.mackie.com	from its published description, but will always equal or exceed the original design specifications unless
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				Part No. 091-221-00 Rev. A 4/03
				Part No. 091-221-00 Rev. A 4/03
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SRM450 specifications

The Mackie SRM450 is a powerful and versatile loudspeaker designed for professionals seeking high-quality sound reinforcement. Known for its robust construction and exceptional audio performance, the SRM450 is a staple in various environments, from concerts and events to installations in venues and churches.

One of the standout features of the SRM450 is its 1000-watt Class D amplifier, which provides plenty of power to drive the speaker to high output levels without distortion. This amplifier is coupled with a high-performance 12-inch woofer and a 1.4-inch titanium dome compression driver, ensuring that the speaker delivers a broad frequency range with clarity and precision. The result is a balanced sound with deep lows, clear mids, and crisp highs, making it suitable for both music and speech applications.

The SRM450 incorporates Mackie’s proprietary Smart Protect DSP technology. This digital signal processing ensures that the speaker operates safely within its limits, preventing overheating and over-driving, which can damage components. Additionally, the speaker offers adjustable EQ settings and a built-in feedback eliminator, which are invaluable tools for live sound engineers.

Portability is another key characteristic of the Mackie SRM450. Weighing in at just around 38 pounds, this speaker is easy to transport and set up, making it ideal for mobile DJs, bands, and event setups. The durable, all-wood cabinet construction enhances sound quality while also contributing to its resilience on the road.

For connectivity, the SRM450 is equipped with a versatile input panel that includes both XLR and 1/4-inch TRS inputs. This allows for easy integration with various audio sources. The built-in mixer with two channels provides additional flexibility, allowing users to connect microphones, instruments, and playback devices directly to the speaker.

Whether used in a small venue or as part of a larger sound system, the Mackie SRM450 stands out for its quality, performance, and reliability. Its thoughtful design and innovative technology make it an excellent choice for sound professionals who demand the best from their equipment. With a reputation for durability and outstanding sound, the SRM450 continues to be a favorite in the pro audio industry, delivering powerful sound and versatility wherever it's needed.