Meyer Sound MM-4CEU - Manual (Page 13)

7
CHAPTER 2
NOTE: Most source equipment is safe for
driving loads no smaller than 10 times the
source’s output impedance.
For source equipment with driving capability of 600 ohms,
16 MM-4CEUs could be safely driven in parallel (10 kOhms
divided by 16 equals 625).
!
CAUTION: Shorting any input connector pin
to the chassis can create a ground loop and
cause hum.
TIP: If abnormal noise (hum, hiss, popping) is
produced from the loudspeaker, disconnect
the audio source from the MM-4CEU. If the noise
stops, the problem is not with the MM-4CEU; check
the audio input and AC power.
LINE LEVEL OUTPUTS
The MM-4CEU features push-pull outputs capable of
driving 600 ohms and using three-pin XLR male connectors
wired as follows:
 Pin 1 — Earth ground/chassis

Pin 2 — Signal +

Pin 3 — Signal -
NOTE: The MM-4CEU is a balanced pass-
through device (balanced signal in - balanced
signal out) and therefore has no effect on the
polarity of the signal it receives. Amplifier XLR
polarity, along with its output wiring, will determine
the polarity of the entire system.
Use standard audio cables with XLR connectors for
driving balanced signal inputs. Telescopic grounding (pin
1 disconnected on one end) is not recommended. Each
MM-4CEU output can drive multiple power amplifier
signal inputs in parallel, to a minimum load impedance of
600 ohms. Refer to your power amplifier specifications
to determine input impedance and calculate the net
impedance of multiple paralleled amplifier inputs. For
example, one channel of a MM-4CEU could drive 20
amplifier channels with 12 kOhms input impedance (600
ohms total impedance).
SPEAkERSENSE INPUTS
For each MM-4CEU channel, connect a cable from the
amplifier output to the corresponding SpeakerSense
input. If you are driving multiple amplifier channels from a
single MM-4CEU output and using MultiSense, connect
the two amplifier output channels with the highest gain
(not to exceed 30 dB of amplification gain) to a separate,
corresponding SpeakerSense input.
!
CAUTION: When using MultiSense, make
sure the two amplifier channels with the
highest gains are the ones connected to each of the
MM-4CEU's two SpeakerSense inputs.
!
CAUTION: When using MultiSense, both
amplifier outputs MUST be connected with
the same polarity. Observe the polarity labels on the
MM-4CEU rear panel.
mm-4CEU/mm-4 CONNECTION DIAGRAm
Figure 2.2 on the following page illustrates a typical
MM-4CEU connection using four 2-channel amplifiers and
32 MM-4 loudspeakers.