Meyer Sound USM-1 - Manual (Page 3)

Operating Instructions
Meyer Sound Laboratories, Inc.
2832 San Pablo Avenue
Berkeley, CA 94702
USM-1
2. Multiple Cabinets. Each cabinet should first be
tested as above.
• Connect one loudspeaker and advance the pink
noise to a convenient measuring level. Position
the measuring microphone between the two
adjacent loudspeakers, and about six feet dis-
tant. Note the frequency response and overall
level.
• Leaving the first loudspeaker connected, con-
Placement of the
USM-1 When the USM-1 is placed on the floor in its nor-
mal position (horn facing up towards the per-
former), there will be a boost in the low frequency
response of the loudspeaker. This is caused by the
loudspeaker coupling with the floor, and may be corrected at the S-1 Control Electronics Unit by
switching in the Lo Cut filter on the Preset Panel, if
desired. Please refer to the S-1 Operating In-
structions for a complete description of its func-
tions.
Rigging The USM-1 loudspeaker has four steel rigging
brackets internally mounted as an integral part of
the cabinet design, and the cabinet is supplied with
aircraft pan fittings (ring and stud), or
3 /
8
"-16 or
M10 x 1.5 nut plates, according to user preference.
A flat plate is supplied when no rigging hardware is
specified. All three plate types are held in place by
six Phillips-head machine screws and can be inter-
changed at any time. The handles on the USM-1
cabinet are provided for moving and carrying
the loudspeaker and are not to be used for
rigging purposes.
The rigging hardware is designed so that a single
point can support the normal load for the cabinet.
In the case of the USM-1, the recommended maxi-
mum load is 420 lbs. (190 kg). 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 com-
petent professionals.
nect the adjacent one and observe the analyzer
display. The entire curve should jump up in
level, indicating correct addition between the
loudspeakers. If the loudspeakers are adjacent,
a polarity reversal between them will show up
as severe broadband cancellation.
As the loudspeakers are moved apart, the can-
cellation will become less apparent at high
frequencies. For this reason polarity testing
should be done with cabinets adjacent.