Meyer Sound MSL-4

Driver Troubleshooting

Troubleshooting with TPL

The TPL LED can indicate serious driver problems, if interpreted

correctly. If one MSL-4 in a system exhibits substantially more

TPL activity than others receiving the same audio signal, then

one or both drivers in that unit may have a short circuit. This

is a potentially dangerous condition for the electronics; shut

the MSL-4 down immediately.

The TPL circuit does not activate if there is no power dissipation

in the driver, regardless of the input signal level. Therefore,

if all MSL-4s in a system receiving the same audio signal

exhibit TPL activity except one, then that unit may have an

open voice coil; disconnect it and contact Meyer Sound for

repair information.

NOTE: The Remote Monitoring System (RMS) provides precise

information about peak power, peak voltage, and average volt-

age (VU) for each ampliﬁer channel, enabling a more complete

driver diagnostic than the TPL LEDs. Contact Meyer Sound for

more information about RMS.

Driver Replacement

To determine whether a low or high frequency driver is functioning

properly, or replace a damaged driver, contact Meyer Sound to

obtain the Low Driver Inspection and Evaluation Procedure

for Self-Powered Series Products (part # 17.010.120.01) or the

High Driver Inspection and Evaluation Procedure for Self-Powered

Series Products (part # 17.010.120.02).

Verifying Driver Polarity

Incorrect driver polarity impairs system performance and may

damage the drivers. All Meyer loudspeakers are shipped with

the drivers in correct alignment. However, if the driver or circuit

wiring has been removed or disassembled in any loudspeaker

in a system for any reason, it is essential to check the polarity

between drivers in the same cabinet and between adjacent

loudspeakers.

We do not recommend using phase poppers to analyze driver

polarity. The phase response for all drivers varies, to some

degree, over the frequency range in which it operates. Since

the phase popper, a popular but inaccurate tool, does not dis-

cern variations in phase response with respect t o frequency,

it provides no useful information about the phase response

through the crossover, the most important consideration for

determining correct driver polarity.

Mid-Hi

DS-2

650-P Subwoofers

CQ Down-fills

DS-2P/DS-4P Mid-Bass

MSL-4 Mid-Hi

Input Mid-Hi

Output

DS-2

Output

Loop

Sub

Output

Input Output

LD-1A

Delay

CP-10 EQ

CH 1

CH 3

Input Output

CH 5

Set the MSL-4 and DS-4P to the same polarity; reverse the

polarity for the CQ. The polarity for the 650-P depends on

the height and distance of the measurement position from the

ﬂown and subwoofer systems.

MSL-4 and 650-R2

Although it is preferable to use the MSL-4 in a completely self-

powered system, excellent results can still be achieved using the

650-R2, USW-1, and MSW-2.

650-R2

subwoofer

CP-10 EQ

(1 Channel)

B-2EX

CEU Amplifier

MSL-4

Set the MSL-4 to the opposite polarity to the 650-R2 ampli-

ﬁer.