Meyer Sound MSL-4

Introduction

The MSL-4 self-powered loudspeaker system is ideal for large

venues requiring long throw distances and precise coverage,

but can also be used effectively in smaller applications. Its high-

Q (narrow coverage) horn has a consistent beam width across

its entire frequency range, enabling efﬁcient array design that

maximizes coverage and SPL for a given array size.

The MSL-4 contains independent ampliﬁer and control

electronics for one 12” low frequency cone driver (in a horn-

loaded vented enclosure) and one high frequency horn driver

(2” throat, 4” diaphragm) in a compact trapezoidal cabinet. This

integrated design provides excellent performance, durabi lity,

and reliability, eliminates ampliﬁer racks, and simpliﬁes

setup and installation.

The MSL-4 matches well with the Meyer Sound DS-4 self-pow-

ered mid/bass loudspeaker, the PSW-2 and 650-P self-powered

subwoofers, and also performs efﬁciently with the PSW-4. The

MSL-4 can be used as a full-range or mid-hi speaker and has

the following acoustical speciﬁcations:

Frequency Response ±4 dB 65 Hz – 18 kHz

Phase Response ±30° 450 Hz – 10 kHz

Coverage 40° H x 35° V

Dynamic Range > 110 dB

The MSL-4 can be equipped to operate with the Remote

Monitoring System™ (RMS) interface network and software

application. RMS displays signal and power levels, driver and

cooling fan status, limiter activity, and ampliﬁer temperature

for all speakers in the network on a Windows-based PC. Contact

Meyer Sound for more information about RMS.

AC Power

When AC power is applied to the MSL-4, the Intelligent AC™

supply automatically selects the correct operating voltage, al-

lowing the MSL-4 to be used in the US, Europe, or Japan

without manually setting a voltage switch. The Intelligent AC

power supply also protects the MSL-4 by performing surge

suppression for high voltage transients (up to 275V), min-

imizing inrush current, and ﬁltering EMI. The MSL-4 uses a

NEMA L6-20P or IEC 309 male power inlet and satisﬁes UL,

CSA, and EC safety standards.

NOTE: Continuous voltages higher than 275V may damage

the unit!

Voltage Requirements

The MSL-4 operates safely and without audio discontinuity if

the AC voltage stays within the ranges 85–134V or 165–264V,

at 50 or 60Hz. Immediately after applying AC power, the green

Active LED on the user panel illuminates and the proper operat-

ing voltage is automatically selected, but the system is muted.

During the next three seconds, the primary fan turns on, the

main power supply slowly ramps on, and the system is enabled

to pass audio signals.

TROUBLESHOOTING NOTE: If the Active LED does not

illuminate or the system does not respond to audio input after

ten seconds, remove AC power to avoid possible damage to

the unit. Experienced electronics technicians with access to a

test bench can verify proper operation for the power supply and

ampliﬁer system with The Meyer Sound Self-Powered Series MP-2

and MP-4 Field Veriﬁcation Procedure (part # 17.022.066.01;

contact Meyer Sound to receive this document). All other users

should contact Meyer Sound or an authorized Meyer Sound

service center.

If the voltage decreases below the lower bound of either op-

erating range (known as a brown-out period), the supply uses

current from its storage circuits and continues to function brieﬂy.

The unit turns off if the voltage does not incre ase above the

threshold before the storage circuits are depleted. The length

of time that the MSL-4 continues to operate during brown-out

depends on how low the voltage drops and the audio source

level during this period.

If the 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 voltage increases above the upper bound of either range,

the power supply turns off rapidly, preventing damage to the

unit.

If the MSL-4 shuts down due to either low or high voltage, the

power supply automatically turns on after three seconds if the

voltage has returned to either normal operating range. If the

MSL-4 does not turn back on after ten seconds, remove AC power

and refer to the TROUBLESHOOTING NOTE above.

Current Requirements

The MSL-4 presents a dynamic load to the AC mains which

causes the amount of current to ﬂuctuate between quiet and

loud operating levels. Since different types of cables and circuit

breakers heat up (and trip) at varying rates, it is essential to un-

derstand the types of current ratings and how they correspond

to circuit breaker and cable speciﬁcations.

The maximum continuous RMS current is the maximum

RMS current over a duration of at least 10 seconds. It is used

to calculate the temperature increase in cables, which is used to

select cables that conform to electrical code standards. It is also