Meyer Sound CAL 32, Руководство по эксплуатации

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CHAPTER 3: CAL USER PANEL
16
The positive (+) and negative (–) pins carry the input as a
differential signal. The shield (S) pin is connected to earth
through a 1 kOhm, 1000 pF, 15 V clamped network. This
circuitry provides virtual ground lift for audio frequencies
while allowing unwanted signals to bleed to ground. When
assembling cables, make sure all three pins are connected
on both ends. Telescopic grounding is not recommended.
Shorting the shield of the audio input to the chassis of the
CAL may cause a ground loop, resulting in hum.
Looping CAL Loudspeakers
The Analog input connectors allow multiple CAL
loudspeakers to be looped from a single audio source.
Connect the loop output pins of the first loudspeaker to the
input pins of the second loudspeaker, and so forth. The loop
output pins are wired in parallel to the input pins and
transmit the unbuffered source signal even when the
loudspeaker is powered off.
To avoid distortion when looping multiple CAL
loudspeakers, make sure the source device can drive the
total load impedance of the looped loudspeakers. In
addition, the source device must be capable of delivering
20 dBV (10 V rms into 600 ohms) to yield the maximum peak
SPL over the operating bandwidth of the loudspeaker.
To calculate the load impedance for the looped
loudspeakers, divide 10 kOhms (the input impedance for a
single CAL) by the number of looped loudspeakers. For
example, the load impedance for 10 CAL loudspeakers is
1000 ohms (10 kOhms / 10). To drive this number of looped
loudspeakers, the source device should have an output
impedance of 100 ohms or less.
NOTE: Most source devices are capable of
driving loads no smaller than 10 times their
output impedance.
NOTE: Make sure that cabling for looped
loudspeakers is wired correctly (shield to
shield, positive to positive, and negative to negative)
to prevent the polarity from being reversed. If one or
more loudspeakers in a system have reversed
polarity, frequency response and coverage can be
significantly degraded.
Digital AES/EBU (4)
The digital input uses a Phoenix 6-pin male connector and
accepts an AES3 digital audio signal. The digital audio
source is received via the connector’s top three pins (shield,
positive, and negative). The connector’s bottom three pins
are not used. The pins for the digital connector are clearly
labeled on the CAL user panel.
NOTE: The AES/EBU port accepts single-
channel (mono) digital audio sources. When
connecting AES/EBU audio sources to CAL, you
must specify in Compass control software whether
the left channel (AES L) or right channel (AES R) will
be used.
Phoenix cable wired for looped audio
From audio
source
To second
loudspeaker
To first
loudspeaker
AES/EBU Input Connector
4
AES/EBU
S
+
-
N
O
T
U
SED