Daisy-Chained; Chapter 4: Using Subwoofers With The Upj-1P; Adding A Line Driver - Meyer Sound Compact VariO UPJ-1P Operating Instructions Manual

CHAPTER 4: USING SUBWOOFERS WITH THE UPJ-1P

A UPJ-1P loudspeaker system can be deployed in
combination with Meyer Sound self-powered USW-1P
compact and 650-P high-power subwoofers. These
subwoofers can achieve very low frequency response
extending system response appreciably and increasing
the overall acoustic power of a system in the lowest
frequencies. The USW-1P subwoofer extends system
frequency response down to 32 Hz, while the 650-P
subwoofers extends system frequency response down to
28 Hz.
In addition, the use of high-pass filters to drive a UPJ-1P
system with subwoofers flattens overall frequency response
and slightly increases UPJ-1P headroom in the lowest end
of its usable spectrum.
The ideal ratio of UPJ-1P loudspeakers to subwoofers
depends on the configuration of the system, the application,
and the frequency content of the signal being reproduced.
For most applications, the following ratios yield good results
in frequency response and headroom:
 Two UPJ-1P loudspeakers for each USW-1P
 Four UPJ-1P loudspeakers for each 650-P
If two UPJs are used per 650-P, the 650-P should have 6 dB
of attenuation for flat frequency response.
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.
There are three basic connection options for these system
configurations.

DAISY-CHAINED

When UPJ-1P 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 re-
sponse will show a rise in the 60 to 200 Hz range where the
loudspeakers' response overlaps at a ratio of two
UPJ-1Ps to each subwoofer.
Make sure the polarity of the UPJ-1Ps and the subwoof-
ers are identical. In a UPJ-1P/USW-1P system, if both
the UPJ-1P and the USW-1P are fitted with the standard
looping module, there is no polarity switch – both are set to
pin 2 +. However, if they are fitted with looping, attenuation
and polarity modules, make sure both are set to the same
polarity.
In the case of a UPJ-1P/650-P system, the 650-P employs
a polarity switch, so you will need to ensure that the 650-P
is set to pin 2 + (same with respect to a UPJ-1P loudspeak-
er's pin 2 +) when co-planar and in close-proximity to the
system.
CAUTION: Make sure that the source equip-
!
ment can drive the total load of the paralleled
system. (See the Audio Input section on page 5.)
NOTE: When a UPJ-1P 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 UPJ-1P 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 UPJ-1P loudspeakers
from the Mid-Hi output of the LD-1A, LD-2 or
LD-3 line driver, with USW-1P or 650-P 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 UPJ-1P loudspeakers and USW-1P or 650-P
subwoofers are separated by a greater distance – or
delay must be used between them – a measurement
system such as Meyer Sound SIM should be used
to determine the correct delay and polarity.
CHAPTER 4
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