SETUP MODE SYSTEM DESCRIPTION AND
USER INTERFACE
The MPM4 is a powerful, feature-filled audio
router and controller. Using the available control
functions, the system installer can make all the
adjustments necessary to provide a transparent,
simple audio manager for the system operator.
Once the system has been properly adjusted, a
password lockout code can be enabled to protect
the setup from unauthorized alterations.
Parameters that can be adjusted include:
Source Input Level Trim.
By trimming all of the Source
Inputs to the same level, the volume in the zones remains
uniform when switching between them. The Trim level
adjustment range is ±20dB in 1dB steps. Each encoder
detent equals 1dB.
Source Input EQ.
A four-band equalizer with a ±15dB
range of adjustment is available on each Source Input for
optimizing its sound. The Lo Mid center frequency is
600Hz and the Hi Mid is 2.5kHz. These are peaking filters.
The Low and Hi frequency bands are shelving types with
different characteristics in boost or cut mode. The Low EQ
boost curve is a shelving type filter with a nominal roll-off
frequency of 80Hz. The Low EQ cut curve has a 12dB per
octave slope with a sliding roll-off frequency. As the
amount of cut is increased, the frequency shifts upward.
Nominal frequency points are 20Hz to 250Hz. The Hi EQ
boost curve is a shelving type filter with a nominal roll-off
frequency of 8kHz. The Hi EQ cut curve has a 12dB per
octave slope with a sliding roll-off frequency. As the
amount of cut is increased, the frequency shifts downward.
Nominal frequency points are 15kHz to 2.5kHz. The EQ
Controls make changes in 1dB increments that are
displayed on the Control Position Indicator LEDs. Each
1dB detent in the Control corresponds with a change in the
display providing precise adjustment throughout the
±15dB range.
Zone Output EQ.
A four-band equalizer is available on
each of the mono Zone Outputs. The range of all four
bands is ±15dB. The Lo Mid and Hi Mid are peaking filters
with frequency centers at 250Hz and 1.6kHz. The Low
and Hi are shelving filters with corner frequencies of 20Hz
and 10kHz. The Lo Mid frequency control peaks at 250Hz,
which enhances upper bass in ceiling/wall mount type
speakers. The Hi Mid frequency control was chosen at
1.6kHz to enhance voice frequencies. The EQ Controls
make changes in 1dB increments that are displayed on the
Control Position Indicator LEDs. Each 1dB detent in the
Control corresponds with a change in the display providing
precise adjustment throughout the ±15dB range.
Zone Max Level.
An appropriate maximum volume for the
listening environment can be established by setting the
audio level going to each Zone Output. This feature allows
the installer to determine the maximum level of all audio
inputs into each zone by coordinating the output gain of the
MPM4 to the inputs of the Zone power amps. This is an
analog final output gain stage with 20dB of gain and 60dB
of attenuation, adjustable in 1dB steps. Each encoder
detent equals 1dB. Unity Gain is at the 0 position of the
Control Position Indicator LED. Output gain, in
conjunction with the of gain and attenuation in the Input
Trim controls and the Priority Assign function allow
manipulation of the signal levels to achieve balance
throughout the system.
Priority Input Level Trim.
The audio level at the Priority
Inputs can be adjusted to compensate for varying output
levels from different types of sources. The Trim level
adjustment range is 0dB to +60dB. Each encoder detent
equals 1dB. The available gain is used to increase paging
mic signals to line level. Line level inputs will require the
use of the Input Pad. This is activated by pushing the rear
panel switch associated with each Priority Input.
Priority Input EQ.
A four-band equalizer with a ±15dB
range of adjustment is available on each Priority Input for
optimizing its sound. The Lo Mid center frequency is
600Hz and the Hi Mid is 2.5kHz. These are peaking filters.
The Low and Hi frequency bands are shelving types with
different characteristics in boost or cut mode. The Low EQ
boost curve is a shelving type filter with a nominal roll-off
frequency of 80Hz. The Low EQ cut curve has a 12dB per
octave slope with a sliding roll-off frequency. As the amount
of cut is increased, the frequency shifts upward. Nominal
frequency points are 20Hz to 250Hz. The Hi EQ boost
curve is a shelving type filter with a nominal roll-off
frequency of 8kHz. The Hi EQ cut curve has a 12dB per
octave slope with a sliding roll-off frequency. As the amount
of cut is increased, the frequency shifts downward.
Nominal frequency points are 15kHz to 2.5kHz. The EQ
Controls make changes in 1dB increments that are
displayed on the Control Position Indicator LEDs. Each
1dB detent in the Control corresponds with a change in the
display providing precise adjustment throughout the
±15dB range.
Priority Assign.
This feature assigns the Priority Inputs to
the Zone Outputs, using the Input First method, and sets
the level of each channel of priority audio within each zone.
The Routing Matrix is used to make the assignments and
the rotary controls are used to set the priority level relative
to the Source Inputs. The adjustment range is ±20dB in
1dB steps. Each encoder detent equals 1dB. In
unassigned zones, the Control Position Indicator LED on
the level controls is set to minimum. Priority Input 1 and
Priority Input 2 have an extra switch on the rear panel that
allows the Priority Input signal to bypass the current setting
of the Zone Volume Controls. With the switches on,
Priority Input 1 and 2 audio is sent directly to the Zone
Outputs at the level determined by the Zone Max Level
setting and all other inputs will be ducked to –70dB
regardless of the position of the Ducking Switch.
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