CHAPTER 2

CHAPTER 2: AMPLIFICATION AND AUDIO

The M2D and M2D-Sub loudspeakers use sophisticated amplification and protection circuitry to produce consistent and predictable results in any system design. This chapter will help you understand and harness the power of the M2D and M2D-Sub amplifier and audio systems.

The rear panels of the M2D and M2D-Sub loudspeakers (Figures 2.1 and 2.2) provide AC connection, audio input, loop out and an interface to the RMS communications module.

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Figure 2.1. The user panel of the M2D loudspeaker

AUDIO INPUT

The M2D and M2D-Sub loudspeakers present a 10 kOhm balanced input impedance to a three-pin XLR connector with the following connectors:

Pin 1 — 220 kOhm to chassis and earth ground (ESD clamped)

Pin 2 — Signal ( + )

Pin 3 — Signal ( - )

Case — Earth (AC) ground and chassis

Pins 2 and 3 carry the input as a differential signal; pin

2 is hot relative to pin 3, resulting in a positive pressure wave when a positive signal is applied to pin 2. Pin 1 is connected to earth through a 220 kOhm, 1000 pF, 15 V clamp network. This ingenious circuit provides virtual ground lift for audio frequencies, while allowing unwanted signals to bleed to ground.

Use standard audio cables with XLR connectors for balanced signal sources. Make sure that pin 1 (shield) is always connected on both ends of the cable. Telescoping grounding schemes are not recommended.

CAUTION: Ensure that all cabling carrying signals to M2D or M2D-Sub loudspeakers in an array is wired correctly: Pin 1 to Pin 1, Pin 2

to Pin 2, and so forth, to prevent the polarity from being reversed. Any number of loudspeakers — even one in the array — with reversed polarity will result in severe degradation in frequency response and coverage.

 

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WARNINGS:

THIS PRODUCT MUST BE GROUNDED

This surface may reach high tempuratures white in use. To ensure proper operation, allow at least 6 inches clearance from this surface and adequate ventilation. To reduce the risk of electric shock do not remove cover. No operator or serviceable parts inside.

Refer servicing to qualified personnel. To reduce the risk of fire or electric shock

do not expose this appliance to rain or moisture.

ATENCI”N: ACCESO INTERNO SOLO

AUTHORIZADO A PERSONAL T…CNICO CALIFICO

ACHTUNG: GEH�USE NICHT OFFENE WARTUNG

UND REPARATUR NUR DURCH ELEKTROF�CHKRAFTE

ATTENTION: ENTRETIENET REPARATIONS

INTERNES NE SONT AUTORISEES QU'AU

PERSONNEL TECHNIQUE QUALIFI…

U.K. WARNING: THIS APPARATUS MUST BE EARTHED.

NO OPERATOR SERVICEABLE PARTS INSIDE.

REFER SERVICING TO QUALIFIED PERSONNEL.

Auto-Voltage Select

95-125V ~

208-235V~

50-60Hz

50-60Hz

1400W RMS MAX 1400W RMS MAX

Operational Voltage Range:

Turn on 85V~ Turn off 134V~

Turn on 165V~ Turn off 264V~

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Audio signals can be daisy-chained using the loop output connector on the user panel (Figure 2.3). A single source can drive multiple M2D or M2D-Sub loudspeakers with a paralleled input loop, creating an unbuffered hard-wired loop connection.

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Figure 2.3. M2D and M2D-Sub user panel audio input connectors

Meyer Sound, Berkeley, CA USA

Figure 2.2. The user panel of the M2D-Sub loudspeaker

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