Chapter 2: Amplification And Audio; Audio Input - Meyer Sound M SERIES Operating Instructions Manual

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
Figure 2.2. The user panel of the M2D-Sub loudspeaker
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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~
Meyer Sound, Berkeley, CA USA

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.
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
CHAPTER 2
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