Meyer Sound Reinforcement Loudspeaker UPM-2 - Manual (Page 2)

Operating Instructions
Meyer Sound Laboratories, Inc.
2832 San Pablo Avenue
Berkeley, CA 94702
UPM-2
Reinforcement
Loudspeaker
Amplifier Requirements The UPM-2 requires a professional quality amplifier rated
at least 125 watts per channel continuously into 16 ohms.
Use of amplifiers of lower power will not allow the full
power and headroom of the UPM-2 to be realized
(though this may be acceptable in applications where high pressure levels are not required). Conversely, use of
amplifiers rated at significantly more than 125 watts into
16 ohms may endanger the loudspeaker, and is not
recommended.
Connections The connection terminals appear on two XLR-type con-
nectors (one male, one female) located on the rear of the
UPM-2 cabinet.
The pin configuration for the XLR-type connectors has
been chosen so that microphone cable (two conductor
and shield) can be used for short speaker runs. The
connection within the cabinet is a loop-through parallel
connection, and the pin assignments are:
Pin 1 — common
Pin 2 — hot
Pin 3 — hot (in parallel with pin 2)
For runs of less than 100' to a single UPM-2 the minimum
recommended wire size is 18 gauge. For parallel connec-
tions, use the loop-through connections at the UPM-2’s
and use a larger gauge cable to the amplifier. Four UPM-
2’s can be run on a single amplifier channel, provided
that the amplifier can drive a four ohm load.
The UPM-2 must be used with the P-2 Control Elec-
tronics Unit. For connections between the CEU and the
power amplifier, refer to its Operating Instructions.
Verifying System
Polarity
The polarity of the UPM-2 loudspeaker is checked at the
factory before shipment, so polarity within the individual
cabinet need only be checked if replacement of a part
becomes necessary. The colored speaker wires attached
to the drivers should be connected to the corresponding
colored terminal on the potted network within the cabinet.
A polarity reversal between the 5" drivers will result in
severe cancellation at 250 Hz and a polarity reversal
between the mid-frequency 5" driver and the tweeter will
show up as a cancellation at 3600 Hz. Either of these
conditions will be very noticeable in frequency response
testing or A/B comparisons with other UPM-2’s.
The “phase-popper” type of speaker polarity checker
cannot reliably be used to test for correct polarity of
multiple UPM-2 cabinets. However, Meyer Sound’s SIM
®
System II many of the portable spectrum analyzers can
be used, with a pink noise source, to test system polarity
as follows:
■ Connect one loudspeaker in the array and advance the
pink noise to a convenient measuring level. Position the
measuring microphone on the axis between the first
loudspeaker and the cabinet adjacent to it, and about 6
feet distant. Note the frequency response and overall
level.
■ Leaving the first loudspeaker connected, connect the
adjacent one and observe the analyzer display. The
entire curve should jump up in level, indicating correct
addition between the loudspeakers. A polarity reversal
between the two loudspeakers will show up as a severe
low-frequency cancellation.
■ Similarly, connect the rest of the cabinets in the array
one by one, looking for correct addition as each loud-
speaker is connected. ( It will be necessary to reposi-
tion the microphone.)
Placement and Arraying The UPM-2 is designed primarily as a supplementary
loudspeaker to provide subtle reinforcement in situations
where the coverage of the main loudspeaker system is
compromised, such as under balconies in theaters or
cabarets. When correctly installed with appropriate delay,
the system can add presence and fidelity to the sound
quality without diverting attention from the main source.
The UPM-2 is suitable for use as a conference-room
sound system for voice reinforcement and music play-
back, and its compact size and high power output capa-
bility makes it appropriate for situations in which a high-
output main system is undesirable, such as in houses of
worship. Further applications include surround channels
in cinema systems, and multimedia room main speakers.
The UPM-2 features even coverage in both the horizontal
and the vertical axis, with high-frequency coverage of 60
°
horizontal and vertical. To increase the coverage angle in
under-balcony situations, place two UPM-2’s end-to-end,
with the tweeters apart. You may separate the angle
between the cabinets to a maximum of 40
°
to increase
the effective coverage angle to 120
°
. For upright (side-
by-side) installation, keep the separation angle between
the two cabinets to at least 20
° and not more than 45 ° .
Always keep the rear corners of adjacent cabinets touch-
ing, where possible.
When the UPM-2 is placed in a corner ( 1 ⁄
4
or 1 ⁄
8
space
loading), the bass response of the system is extended by
up to an octave. If this additional response is not re-
quired, engage the Lo Cut switch of the P-2 to insert a
160 Hz high-pass filter.