Specifications

penetrating where acoustics are "dead" or where sing-
ers' voices must compete with loud amplified instruments
on stage.
HOOKUP
Amplifiers
The 701 is designed for use with the Shure Model 700
Power Console and similar amplifiers having the follow-
ing maximum power output capabilities.
Voltage
Preferably, each speaker should be connected to a
separate amplifier output jack to minimize power losses
in the cable. Two parallel-wired jacks are provided on
the back of each 701 Speaker System. This allows con-
necting two speakers by connecting the first speaker to
the amplifier and the second speaker to the first. This
may be helpful in certain room shapes. However, when
speakers are connected in this manner, the next heavier
wire gauge is recommended between the amplifier and
the first speaker. Therefore, for two speakers connected
together where the first is at a distance of 30m (100 ft)
from the amplifier, use No. 14 AWG cable between the
amplifier and the first speaker; for two speakers where
the first is at 15m (50 ft), use No. 16 AWG cable between
the amplifier and the first speaker. When positioning the
speaker cables, place them where the audience, per-
formers, or passers-by will not trip over them.
To avoid frequency response aberrations, poor cover-
age, and dead zones caused by improper speaker phas-
ing in multiple speaker installations, all speakers must
be wired with the same polarity. The cables listed in the
chart above are color-coded to ensure that identical con-
nections are used. Note that even common 18-gauge
lamp cord ("zip" cord) is phase-coded with ribs along
the outer jacket of one conductor.
The cable can be stored in the convenient snap-pocket
of the optional slip-on cover for the 701 speaker.
25-Volt Line Operation
The 701 can be operated from a 25-volt line without
the need for an accessory transformer. Note that the
speaker will draw 78 watts when connected to a con-
stant-voltage, 25-volt line.
Continuous Power To:
16 ohms 8 ohms 4 ohms
34.6 Vrms
(55V peak)
70-Volt Line Operation
For operation from a 70-volt line, a transformer such
as the Shure Model
A102A, providing power taps of 50,
25, 12, and 6 watts, should be used.
75 watts 150 watts 300 watts
CHECKING SOUND COVERAGE
Speaker Wiring
Fifteen meters (50 ft) of cable is supplied with each
701 Speaker System. For convenient attachment, a
straight phone plug and a right-angle phone plug are
provided. Connect either end to the back of the speaker
and to the Power Console amplifier. The supplied cable
is 18 gauge (No. 18 AWG) and can be used for cable runs
of up to 15m (50 ft) between the speaker and the ampli-
fier. If cable runs longer than
15m are required, use the
following table to determine the correct wire gauge.
Maximum
Distance From
Power Console
Amplifier Wire Gauge Recommended Cables
15m (50 ft) AWG 18 Belden
#8460, #8461,
#9470, #8542
30m (100 ft) AWG 16 Belden #8470, #8471,
# 8472
60m (200 ft) AWG 14 Belden
#8473
After the 701 speakers, Power Console amplifiers,
and other equipment have been installed and connected,
sound coverage can be checked as follows.
1. Apply a fairly constant-level signal to the system
(preferably low-level pink noise* or program mate-
rial) and walk around the audience area. Listen for
a smooth, even output from the speakers, with min-
imal differences in volume and tone, and no "dead"
spots or phase distortion.
A. A dead spot-for audio purposes, where no direct
sound is heard, or where the sound level is ap-
preciably lower-may mean that the speakers
are not covering that area, or that the speaker
wires are connected out-of-phase. Proper phas-
ing can be readily determined by checking the
connections on each speaker, but inadequate
coverage generally requires repositioning the
speakers. The dead area should be examined
carefully to determine that the problem can be
corrected without resorting to auxiliary speakers.
B. Phase distortion-a type of distortion distinguish-
able by being heard only in parts of the audience
area-can be due to overlapping areas of speak-
er coverage or sound reflecting off hard surfaces.
Re-aim the speakers or change the horn angle to
60" from 120" to eliminate this kind of distortion.
2. Use an Equalization Analyzer System such as the
Shure Model
M615AS to supply and analyze a pink
noise signal. An octave equalizer like the ones found
on the Shure Model 700 PRO
MASTERTM Power Con-
sole (or separate equalizers like the Shure Models
SR107 or M610) can be used to adjust the sound
system for optimum equalization and maximum gain
before feedback.
General
The 701 Speaker System can be modified for biampli-
fied operation-where separate power amplifiers are
used for high and low frequencies and are connected
individually to the high and low frequency speaker sec-
tions. The advantage of biamplification is the elimination
of high-frequency and intermodulation distortion caused
by high-level low-frequency signals. The separate power
amplifiers used in biamplification achieve the optimum
matching of power available and maximize acoustic out-
put.
Modification of the 701 for Biamplified Operation
1. Remove the 15-inch woofer as described in the
Service Instructions. Take care not to break the
leads to the speaker terminals or damage the cone.
2. Cut the red jumper lead that connects the two jacks
on the panel inside the cabinet. Insulate both ends
of the red jumper lead.
3. Note to which jack the woofer is directly connected.
On the outside of the cabinet, mark this jack "LOW";
mark the other jack "HIGH".
4. Replace the woofer as described in the Service
Instructions.
Sine-wave signals delivering 150 watts to a speaker should be avoided
because they present a much greater average power than does pink noise
or program material. Consequently, when setting up or adjusting a sound
system with the
701 speaker, avoid the use of high-level, continuous-type
test signals.