Page 1
UPA-1C
Loudspeaker
Operating Instructions
The Meyer Sound UPA-1C is a compact, high-power
arrayable loudspeaker designed to perform in a wide
variety of sound reinforcement applications. It is a biamplified system consisting of a proprietary 12-inch
low-frequency cone driver in a vented enclosure with
an 80-degree horizontal high-frequency horn and
driver.
Meyer Sound Laboratories, Inc.
2832 San Pablo Avenue
Berkeley, CA 94702
The UPA-1C is designed to be operated as a system
with the Meyer Sound M-1A Control Electronics
Unit (one M-1A per channel). The M-1A comprises
electronic crossover, Meyer Sound exclusive
SpeakerSense™ driver protection circuitry, and
amplitude and phase response alignment circuitry
optimized for the loudspeaker.
Page 2
UPA-1C
Loudspeaker
Operating Instructions
Amplifier Requirements The UPA-1C requires a professional quality two-channel
power amplifier rated at 200-300 watts per channel
continuous into 8 ohms. (If two UPA-1Cs are to be operated
in parallel from the amplifier, it should be capable of driving
4 ohms.) Use of amplifiers of lower power will not allow
the full power and headroom of the UPA-1C system to be
realized (though this may be acceptable in applications
Connections The UPA-1C is a biamplified system and must be used with
Verifying System Polarity
the M-1A Control Electronics Unit. The M-1A functions as
an active crossover, dividing the input signal into high and
low frequency components.
The connection terminals of the low and high frequency
drivers appear on a single EP-type 4-pin connector located
on the rear of the UPA-1C cabinet. The pin assignments for
this connector are:
Pin 1 – 12-inch driver, hot
Pin 2 – 12-inch driver, common
Pin 3 – horn driver, common
Pin 4 – horn driver, hot
(When the cabinet is fitted with a EP-5 connector, Pin 5 is
unconnected.)
The minimum wire size for connections between the UPA1C and the power amplifier should be 14 gauge.
All Meyer Sound loudspeakers are thoroughly tested in all
stages of manufacture and correct polarity of individual
cabinets is assured. However, accidental polarity reversal
is possible when there are multiple amplifier connections. A
single cabinet which is 180 degrees out of polarity with the
rest of the system will cause severe cancellation, resulting in
a noticeable decrease in SPL and possible component
damage.
The preferred method for testing Meyer Sound loudspeakers
is to use SIM® System II. Alternatively, many of the portable
spectrum analyzers can be used, with a pink noise source,
to test for driver polarity as follows:
1. Single cabinets
First, verify polarity of the woofer by connecting a 9 volt
battery at the end of the loudspeaker cable.
Connector Battery
Pin 1 +terminal
Pin 2 - terminal
■ The woofer cone should move outward toward the listener.
Connect the speaker cable to the amplifier.
■ Input the pink noise source to the M-1A and advance the
M-1A. Level control to a convenient measuring level.
■ Standing in front of the loudspeaker, position the analyzer
microphone directly between the horn and the 12-inch
driver, at right angles to the cabinet face, and about
20 inches in front of the UPA-1C.
where high pressure levels are not required). Conversely,
use of amplifiers rated at significantly more than 300 watts
per channel into 8 ohms may endanger the loudspeaker,
and is not recommended.
Note: If you are using standard Meyer Sound loudspeaker
cables and adapters, simply connect the female end of
the loudspeaker cable to the UPA-1C, the male end of the
cable to the Meyer Sound pigtail adapter, and the banana
connectors of the adapter to your amplifier outputs. In
making connections between the UPA-1C and the amplifier,
be sure to connect the 12-inch driver to the Lo channel, and
the horn driver to the Hi channel.
The adapter banana plugs are color-coded as follows:
Red – Low frequency driver
Black – High frequency driver
For connections between the M-1A and the power amplifier,
refer to the M-1A Operating Instructions
2.Multiple cabinet arrays
Each cabinet should first be tested as above.
■ 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 six
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 loudspeakers will show up as severe
broadband cancellation.
■ Similarly, connect the rest of the cabinets in the array
one by one, looking for correct addition as each
loudspeaker is connected. (It will be necessary to
reposition the microphone.)
Note: A polarity reversal within the system can result in
severe damage to the components. It is strongly
recommended that polarity testing be done at low levels
and with the appropriate equipment.
■ If the polarity of the horn driver is reversed, a trough will
appear in the response curve, centered near 1600Hz. If
in doubt, reverse the polarity of the Hi amplifier output
while you watch the analyzer display.
Meyer Sound Laboratories, Inc.
2832 San Pablo Avenue
Berkeley, CA 94702
Page 3
UPA-1C
Loudspeaker
Operating Instructions
Rigging The UPA-1C loudspeaker has four steel rigging brackets
Placement and
Arraying
High Frequency
Network
internally mounted as an integral part of the cabinet design
and the cabinet is supplied with either aircraft pan fittings
(ring and stud), 3/8" -16 or M10 nut plates, according to user
preference. A flat plate is supplied when no rigging
hardware is specified. All plates are held in place by six
Phillips-head machine screws and can be interchanged at
any time. The handles on the UPA-1C cabinet are provided
solely for moving and carrying the loudspeaker and are not
to be used for rigging purposes.
The high frequency horn of the UPA-1C adds very well in
the horizontal axis, and the apparent sources of both high
and low frequencies in the UPA-1C are co-planar in terms
of propagation. For these reasons, multiple loudspeakers
may be built into an array which behaves acoustically as a
section of a radiating spherical surface. Such arrays offer
precisely controlled coverage and propagate coherent
wavefronts, acting as a close approximation to a point
source. These are the basic rules for forming arrays with
the UPA-1C.
The UPA-1C loudspeaker contains, mounted in the
enclosure, a DC protection and response correction
network for the high-frequency horn driver. The network is
mounted directly behind the MS-12 low-frequency cone
driver on the inside rear face of the cabinet, and is wired in
series with the horn driver.
The circuit board is fitted with five terminals, two of which
(labeled AMP- and AMP+) are wired to the Cannon EP-4
connector pins 3 and 4. The other terminals (labeled FLAT
and 16KPK), provide two options for tailoring the system’s
response. With the high driver common (green) wire
connected to the FLAT terminal, the UPA-1C highfrequency response is nominally flat to 20 kHz. When the
The rigging hardware is so designed that a single point can
support the normal load for the cabinet. In the case of the
UPA-1C the recommended maximum load is 420 lbs
(190 kg) (for example, the weight of the cabinet itself plus
an MSL-3A and a UPA-1C hung beneath). Any of the
individual rigging points is capable of supporting this load
with an adequate safety margin. However, Meyer Sound
strongly recommends that safety lines be run to the other
points. If the structural integrity of any cabinet has been
compromised by damage or negligence, then the safety of
the rigging cannot be assured. All rigging should be done
by competent professionals.
■ Keep the rear corners of adjacent loudspeakers together
or close to one another.
■ For wider horizontal coverage, spread the angle
between adjacent loudspeakers (to a maximum 45
degrees), by moving the front corners apart. For even
frequency response with two UPA-1C, the minimum
separation angle between cabinets should be 15
degrees.
common wire is connected to the 16KPK terminal, the UPA1C exhibits a peaked response in the 16 kHz region. This
response may be useful for overcoming propagation losses
when far-field response is a dominant concern.
The UPA -1C is shipped with the high driver common
connected for flat response. Should you desire more highfrequency energy, simply remove the six bolts holding the
MS-12 in place, pull the MS-12 up and out of the cabinet,
and move the green wire from the FLAT terminal to the
16KPK terminal. Be careful not to disturb the other wires to
the network board or EP connector. When replacing the
MS-12, be certain to tighten the six bolts evenly.
AMP+
WHT
AMP -
GRN
©1992 Meyer Sound Y-1PD PCB
Meyer Sound Laboratories, Inc.
2832 San Pablo Avenue
Berkeley, CA 94702
Assy. # 24.052.103._________Rev_________
UPA-1C High Frequency Network Circuit Board
TESTED:_________
DATE:___________
DRVR+
WHT
FLAT
DRVRGRN
16KPK
Page 4
UPA-1C
Loudspeaker
Specifications Acoustical–UPA-1C/M-1A System
Note 1:
Measured 1 meter from center
of cabinet face, half-space
conditions, pink noise input,
network set to FLT, smoothed
to one-third octave. Low
frequency response dependent
on load conditions.
Note 2:
Loudspeaker driven with pink
noise.
Operating Instructions
Frequency Response
1
80 Hz to 18 kHz +4dB
-6 dB at 60 Hz and 20 kHz
Maximum SPL2 with amplifier rated at: 25 0W/8 ohms/ch 60W/8 ohms/ch
Continuous 125dB 120dB
Peak 132dB 125dB
HF Coverage
Horizontal 80 degrees
Vertical 60 degrees
UPA-1C Loudspeaker
Driven Complement
Low Frequency Driver MS-12
High Frequency Driver MS-1401B
High Frequency Horn Modified radial with foam lens
HF Network Y-1PD
Function DC blocking and damped band-elimination filter
Enclosure 0.8 cu. ft. vented, multi-ply
Finish Black textured, weather protected (optional)
Physical Dimensions 141/2"W x 22 3/8"H x 141/2"D
Weight 67 lbs. (30 kg)
Protective Grill Perforated steel screen,
Connector EP-4 (male), EP-5 (male, Europe only)
Rigging (optional) Aircraft pan fittings, or 3/8"-16 or M10 x 1.5 nut plate
Finnish Birch plywood
charcoal-grey foam covering
Meyer Sound Part Number
05052012.03 Revision A3.
January 1994
© Meyer Sound, 1985 - 1994. All
rights reserved. This document
may not be reproduced without
permission.
Coverage Angle
1
Vertical 60°
Horizontal 80°
Maximum SPL @ 1meter
Continuous 125 dB
Peak 135 dB
Total Amplifier Power 450 watts
Narrow Horizontal Coverage Array
Coverage Angle
1,3
Vertical 60°
Horizontal 130°
Maximum SPL @ 1meter
Continuous 129 dB
Peak 139 dB
Total Amplifier Power 900 watts
Wide Horizontal Coverage Array
Coverage Angle
15°
Vertical 60°
1,3
Horizontal 140°
Maximum SPL @ 1meter
Continuous 129 dB
Peak 139 dB
Total Amplifier Power 900 watts
Long Throw High Power Array
Coverage Angle
1,3
Vertical 30°
Horizontal 130°
Maximum SPL @ 1meter
Continuous 135 dB
Peak 145 dB
Total Amplifier Power 1.8kw
Wide Vertical Coverage Array
Coverage Angle
1,3
2
Vertical 100°
30°
Horizontal 80°
Maximum SPL @ 1meter
Continuous 125 dB
Peak 135 dB
Total Amplifier Power 900 watts
1
Coverage angle is the -6dB average. All measurements made at
24 inches and confirmed at 6 feet (on-axis except where noted)
using pink noise source and measured in 1/3rd octave bands.
2
This configuration produces smooth response, but is asymmetrical
in the vertical plane. (Measurement axis same as for a single UPA1C).
3
Frequency response 50Hz – 16kHz, half-space conditions.
Meyer Sound Laboratories, Inc.
2832 San Pablo Avenue
Berkeley, CA 94702
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