Meyer Sound M1D - Manual (Page 14)

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CHAPTER 2
9
CHAPTER 2
M1D Interconnections
For the low to low-mid frequencies, the M1D loudspeaker
utilizes two 8 ohm, 5-inch cone drivers. These drivers are
rated to handle 200 AES watts (loudspeaker driven with a
band-limited noise signal with 6-dB peak-to-average ratio
for a period of 2 hours).
A complex passive network connected between the ampli-
fier and the drivers is used to ensure smooth response in
the critical midrange. At the lowest frequencies, the two 5-
inch drivers combine to reproduce coherent low frequen-
cies. In the mid frequencies, the passive network feeds
only one of the two drivers while correcting the phase shift
at low frequencies for proper addition with the other driver.
This technique eliminates interference between the high-
frequency and low-frequency drivers that would otherwise
occur near the crossover frequency, and maintains optimal
polar and frequency response characteristics.
To reproduce high frequencies, the M1D loudspeaker em-
ploys three high-power neodymium magnet metal dome
tweeters coupled to a 100° constant-directivity horn. The
tweeters behave like a small line array affording very tight
vertical coverage while utilizing the M1D wave guide to
provide wide horizontal coverage.
!
CAUTION: All Meyer Sound loudspeakers
are shipped with the drivers in correct align-
ment. However, if a driver needs to be replaced,
make sure the replacement is reinstalled with the
correct polarity. Incorrect driver polarity impairs the
system performance and may damage the drivers.
M1D Amplification and Limiting
All five drivers in the M1D loudspeaker are powered by
a two-channel proprietary Meyer Sound amplifier utiliz-
ing complementary MOSFET output stages (class AB/
bridged) capable of delivering 500 watts total. The ampli-
fier employs electronic crossover, phase, and frequency
response correction filters as well as protection circuitry to
process the audio signal. All the specific functions for the
M1D loudspeaker are determined by the control module
installed inside the amplifier; one channel of the amplifier
drives the low and low-mid section of the M1D loudspeak-
er through the passive network while the other channel
drives the high frequency section.
Each channel of the amplifier has peak and rms limiters
to prevent driver over-excursion and regulate the tem-
perature of the voice coil. Limiter activity for high and low
channels is indicated by two yellow Limit LEDs on the
M1D rear panel (Figure 2.2).
Figure 2.2: M1D high-frequency and low-frequency limiter activity is
shown by the Limit LEDs.
M1D-Sub Interconnections
The M1D-Sub loudspeaker utilizes two 4 ohm, 10-inch,
cone drivers. These newly developed drivers feature
lightweight neodymium magnet structures and are rated to
handle 400 AES watts (loudspeaker driven with a band-
limited noise signal with 6-dB peak-to-average ratio for a
period of 2 hours).
! CAUTION: All Meyer Sound loudspeakers
are shipped with the drivers in correct align-
ment. However, if a driver needs to be replaced,
make sure the replacement is reinstalled with the
correct polarity. Incorrect driver polarity impairs the
system performance and may damage the drivers.
M1D-Sub Amplification and Limiting
Each 10-inch cone driver in the M1D-Sub loudspeaker
is powered by one channel of a two-channel proprietary
Meyer Sound amplifier capable of delivering 450 watts to-
tal. The amplifier employs electronic crossover, phase, and
frequency response correction filters as well as protection
circuitry to process the audio signal. All of the specific
functions for the M1D-Sub are determined by the control
module installed inside the amplifier; a limiter controlling
both channels prevents driver over-excursion and regu-
lates the temperature of the voice coil. Limiter activity is
indicated by the lower yellow Limit LED on the M1D-Sub
rear panel, as shown in Figure 2.3.
Figure 2.3: M1D-Sub limiter activity is shown by the Limit LEDs.
high-frequency LED (yellow)
low-frequency LED (yellow)
not used
M1D-Sub limit LED