Chapter 4: Using Subwoofers With The Upm-1P And Upm-2P; Daisy-Chained; Adding A Line Driver - Meyer Sound UPM-1P Operating Instructions Manual

CHAPTER 4: USING SUBWOOFERS WITH THE UPM-1P AND UPM-2P

UPM-1P and UPM-2P loudspeakers can be deployed in
combination with Meyer Sound self-powered USW-1P
compact and UMS-1P ultra-compact subwoofers. These
subwoofers are capable of producing very low frequencies
and extending overall system response appreciably and
increasing the acoustic power of a system in the lowest
frequencies. The UMS-1P and USW-1P extend system
frequency response down to 29 Hz and 30 Hz, respectively.
In addition, the use of high-pass filters to drive a UPM-1P or
UPM-2P system with subwoofers flattens overall frequency
response and slightly increases UPM-1P or UPM-2P
headroom in the lowest end of their usable spectrum.
The ideal ratio of UPM-1P or UPM-2P loudspeakers to
subwoofers depends on the configuration of the system,
the application, and the frequency content of the signal
being reproduced. For most applications, a ratio of two
UPM-1P or UPM-2P loudspeakers for each UMS-1P
subwoofer and four UPM-1P or UPM-2P loudspeakers for
each USW-1P subwoofer yields good results in frequency
response and headroom.
NOTE: The limit LEDs indicate when
the safe power level is exceeded. If the
subwoofers used in the system begin to limit before
reaching the required SPL at low frequencies,
consider adding more subwoofers to satisfy the
SPL requirements without exposing the drivers to
excessive heat and/or excursion.
Three basic connection options exist depending on your
system configuration.

DAISY-CHAINED

When UPM-1P or UPM-2P loudspeakers and subwoofers
are daisy-chained using the loop feature on the user panel,
the result will be a fairly flat frequency response. However,
the response will show a rise in the 60 to 200 Hz range
where the loudspeakers' response overlaps at a ratio of two
UPM-1P or UPM-2P loudspeakers to each subwoofer.
Make sure the polarity of the UPM-1P or UPM-2P
loudspeakers and the subwoofers are identical. If the
UPM-1P/UPM-2P and the USW-1P or UMS-1P are both
fitted with the standard looping module, there is no polarity
switch; all loudspeakers in the system are set to pin
2+. However, if they are fitted with looping, polarity and
attenuation audio input modules, make sure both are set to
the same polarity.
CAUTION:
Make sure that the source
!
equipment can drive the total load of the
paralleled system. (See the Audio Input section on
page 9.)
NOTE: When a UPM-1P or UPM-2P
loudspeaker and a subwoofer are used in their
full-range configuration (e.g., looped audio or the
same audio feed), their polarities should be kept the
same if they are co-planar or near to each other. If
they are separated by a greater distance — or delay
must be used between them — a measurement
system such as Meyer Sound's SIM
should be used to determine the correct delay and
polarity.

ADDING A LINE DRIVER

Driving a UPM-1P or UPM-2P loudspeaker system
and subwoofers with the same signal from different
outputs using a line driver allows adjustments to the gain
and polarity of each sub-system. This could be used
effectively to compensate for the ratio of loudspeakers or
acoustical conditions. If gains are adjusted to the same
level, the combined response is identical to a daisy-chain
configuration with a rise in level in the overlapping range.
NOTE:
When driving UPM-1P and/or
UPM-2P loudspeakers from the Mid-Hi
output of the LD-1A, LD-2 or LD-3 line driver, with
USW-1P or UMS-1P subwoofers driven from the
subwoofer output in their full-range configuration,
their polarities should be kept the same if they are
co-planar or near each other.
If the UPM-1P/UPM-2P loudspeakers and USW-1P or
UMS-1P subwoofers are separated by a greater distance
— or delay must be used between them — a measurement
system such as the SIM audio analyzer should be used to
determine the correct delay and polarity.
CHAPTER 4
audio analyzer
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