CHAPTER 1

M2D-Sub Voltage Requirements

The M2D-Sub loudspeaker operates safely and without audio discontinuity if the AC voltage stays within either of two operating windows at 50 or 60 Hz:

85 to 134 volts

165 to 264 volts

CAUTION: Continuous voltages higher than 264 volts can damage the unit.

After applying AC power, the proper operating voltage is automatically selected, but the system is muted. During the next three seconds the following events occur:

1.The primary fan turns on.

2.The main power supply slowly ramps on.

3.The green Active LED on the User Panel lights up, indicating that the system is enabled and ready to pass audio signals.

CAUTION: If the Active LED does not illuminate or the system does not respond

to audio input after ten seconds, remove AC power immediately. Verify that the voltage is within the proper range. If the problem persists, please contact Meyer Sound or an authorized service center.

If voltage drops below the low boundary of either safe operating range (brownout), the M2D-Sub loudspeaker uses stored energy to continue functioning briefly, and shuts down only if voltage does not rise above the low boundary before the M2D-Sub loudspeaker’s storage circuits are depleted. How long the loudspeaker will continue to function during brownout depends on the amount of voltage drop and the audio source level during the drop.

If the voltage increases above the upper boundary of either range, the power supply rapidly turns off, preventing damage to the unit.

NOTE: If voltage fluctuates within either operating range, automatic tap selection stabilizes the internal operating voltage. This tap

selection is instantaneous, and there are no audible artifacts.

If the M2D-Sub loudspeaker shuts down due to either low or high voltage, its power supply automatically turns on after three seconds if the voltage has returned to either normal operating window. If the M2D-Sub does not turn back on after ten seconds, remove AC power immediately (see previous Caution).

NOTE: It is recommended that the supply be operated in the rated voltage windows at

least a few volts away from the turn on/off points. This ensures that that AC voltage variations from the service entry – or peak voltage drops due to cable runs – do not cause the amplifier to cycle on and off.

M2D-Sub Current Requirements

The M2D-Sub loudspeaker presents a dynamic load to the AC mains, which causes the amount of current to fluctuate between quiet and loud operating levels. Since different cables and circuit breakers heat up at varying rates, it is essential to understand the types of current ratings and how they correspond to circuit breaker and cable specifications.

The maximum long-term continuous current is the maximum rms current during a period of at least ten seconds. It is used to calculate the temperature increase in cables, in order to select a cable size and gauge that conforms to electrical code standards. It is also used to select the rating for slow-reacting thermal breakers.

The burst current is the maximum rms current during a period of approximately one second, used to select the rating for most magnetic breakers and to calculate the peak voltage drop in long AC cables according to the formula:

V pk (drop)= I pk x R (cable total).

The ultimate short-term peak current is used to select the rating for fast-reacting magnetic breakers.

Use Table 1.2 below as a guide when selecting cable gauge size and circuit breaker ratings for your operating voltage.

Table 1.2. M2D-Sub Current Ratings

Current Draw

115 V AC

230 V AC

100 V AC

Max. long-term

8.8 A rms

4.4 A rms

10 A rms

continuous

 

 

 

 

 

 

 

 

 

 

Burst current

19

A rms

9.5 A rms

22 A rms

 

 

 

 

 

 

Ultimate short-

39

A pk

20 A pk

45

A pk

term peak

 

 

 

 

 

 

 

 

 

 

Idle current

1.2 A rms

0.6 A rms

1.3

A rms

 

 

 

 

 

 

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