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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 to 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
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.
