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650-R2
Reinforcement
Subwoofer
Operating Instructions
Meyer Sound Laboratories, Inc.
2832 San Pablo Avenue
Berkeley, CA 94702
The 650-R2 requires a professional quality two-channel
power amplifier capable of delivering up to 350 watts per
channel into 8 ohms or 750 watts per channel into 4 ohms
(FTC rating). Use of amplifiers of lower power will not allow
the full power and headroom of the 650-R2 system to be
realized. Where the B-2EX Control Electronics is used, the
650-R2 will safely handle amplifiers rated at up to 1500
watts per channel if the B-2EX Safe switch is engaged.
Note. The 650-R2 may be used with any of the following
Meyer Sound Control Electronics Units: B-2, B-2A, B-2AEX
and B-2EX. Only the B-2AEX and B-2EX contain excur-
sion protection circuitry to allow use with amplifiers
rated over 750 watts at 4 ohms.
Amplifier Requirements
The connection terminals of the 18-inch driver appear on
an EP-type 4-pin connector located on the rear of the
650-R2 cabinet. Pin assignments for this connector are:
Pin 1 — Driver 2, common (–)
Pin 2 — Driver 1, common (–)
Pin 3 — Driver 1, hot (+)
Pin 4 — Driver 2, hot (+)
(When the cabinet is fitted with an EP-5 connector, pin 5 is
unconnected.)
The minimum wire size for connections between the
650-R2 and the power amplifier should be 14 gauge.
Note: If you are using standard Meyer Sound Ioudspeaker
cables and adapters, simply connect the female end of the
loudspeaker cable to the 650-R2, the male end of the cable
to the Meyer Sound subwoofer pigtail adapter, and the
banana connector of the adapter to your amplifier outputs.
For connections between the B-2EX and the power ampli-
fier, refer to the B-2EX Operating Instructions.
Connections
Verifying System
Polarity
All Meyer Sound Ioudspeaker systems are thoroughly
tested in all stages of manufacture and the correct polarity
of individual cabinets is assured. However, polarity reversal
is possible in systems with multiple amplifier connections.
A single cabinet or component that is out of polarity with
the rest of the system will cause phase cancellation,
resulting in a noticeable decrease in SPL and possible
component damage.
The polarity of individual cabinets may be tested with a
9 volt battery, and Meyer Sound’s SIM
®
System II or a
spectrum analyzer can be used, with a noise source, to test
for correct polarity between cabinets.
1. Single cabinets.
■ First verify polarity of the drivers by connecting a 9 volt
battery at the end of the Ioudspeaker cable:
EP connector Battery
Pin 1 - terminal
Pin 4 + terminal
■ The woofer cone should move outward toward the
cabinet front face.
■ Now repeat the process with the other driver, connect-
ing pin 2 to the minus terminal and pin 3 to the plus.
2. Multiple cabinets.
■ Each cabinet should first be tested as above.
■ Input the pink noise source to the B-2EX.
■ Connect one cabinet and advance the pink noise to a
convenient measuring level. Position the measuring
microphone on the axis between two adjacent cabinets,
and about 6 feet distant. Note the frequency response
and overall level
■ Leaving the first cabinet connected, connect the adja-
cent one and observe the analyzer display. The entire
curve should jump up in level, indicating correct addi-
tion between the loudspeakers. A polarity reversal
between the loudspeakers will show up as severe
cancellation.
Similarly, connect the rest of the cabinets in the array one
by one, looking for correct addition as each Ioudspeaker is
connected. (It will be necessary to reposition the micro-
phone.)
Note: A polarity reversal within a subwoofer system can
result in severe damage to the drivers. It is strongly recom-
mended that polarity testing be done at low levels and with
the appropriate equipment.
Verifying Crossover to
Full-Range System
Phase cancellations very often occur between subwoofers
and the full-range system that they supplement, dependent
upon their placement, because of the long wavelengths at
which they operate. For example, the wavelength of sound
at 100 Hz is approximately 11 feet, so a displacement of
5
1
⁄
2
or 16
1
⁄
2
feet between the subwoofers and the main
system will cause them to be out of phase with one another
at 100 Hz. This will result in cancellation at that frequency.
In some placements of 650-R2’s, there may be such a
phase cancellation at crossover. But in other placements,
or in similar placements with different boundary conditions,
this cancellation may not occur. In all cases, the correct
polarity for the subwoofer is the connection that results in
good addition at the crossover frequency (100 Hz).
The 650-R2 should always be tested to verify its behavior
at crossover to the main system, and this may be done
through frequency response verification using Meyer
Sound’s SIM
®
System II or a third-octave RTA with pink
noise. If there is a cancellation at approximately 100 Hz,
reverse the polarity of the subwoofers.