Manual-6
d. Do not adjust amplifier sensitivity controls after you have
set crossover Output Levels.
e. Place the RA 30 analyzer microphone about 24 inches
[60 cm] away from the speaker stack, as close to equidistant
to each driver as possible (see Figure 4).
f. Set the RA 30 Source to CAL MIC.
g. Set the RA 30 to RTA Mode.
h. Set the RA 30 RTA scale to 1 dB.
i. Turn on the RA 30 Pink Noise.
j. Turn on the amplifiers.
5. Set the Delays starting with the driver furthest back (the one
that gets zero delay) and work outward (see Figure 4).
6. Hi-Mid / High Delay alignment:
a. Place CAL MIC in Position 1 as shown in Figure 4.
b. Set reference level for AC 24 High Output:
i)
Un
MUTE the High Output.
ii) Adjust the High Output LEVEL control so that an
adequate pink noise level is present.
iii) Press NORM on the RA 30 (some LEDs in High
Output passband should indicate green).
iv) Adjust the High Output LEVEL so the RA 30 LED,
at the Hi-Mid / High crossover frequency, is green.
v) MUTE the High Output.
c. Set reference level for AC 24 Hi-Mid Output:
i)
Un
MUTE the Hi-Mid Output.
ii) Adjust the Hi-Mid Output LEVEL so the RA 30
LED, at the Hi-Mid / High crossover frequency, is
green.
d. Set the High Output DELAY:
i) Referring to Figure 4, note the Hi-Mid Output is
the furthest back and requires no delay.
ii)
Un
MUTE the Hi-Mid and High Outputs.
iii) If the level goes down, driver polarity may be
wrong. Check the driver polarity before proceeding.
iv) Adjust the High Output DELAY for maximum
signal level in the RA 30 RTA band associated with
the Hi-Mid / High crossover frequency.
7. Mid / Hi-Mid Delay alignment:
a. Place CAL MIC in Position 2 as shown in Figure 4.
b. Set the reference level for Hi-Mid Output:
i)
Un
MUTE the Hi-Mid Output.
ii) Adjust the Hi-Mid Output LEVEL so the RA 30
LED, associated with the Mid / Hi-Mid crossover
frequency, is green.
iii) MUTE the Hi-Mid Output.
c. Set the reference level for the Mid Output:
i)
Un
MUTE the Mid Output
ii) Adjust AC 24 Mid Output Level so the RA 30 LED,
associated with the Mid / Hi-Mid crossover frequency,
is green.
d. Set Mid Output Delay:
i) Referring to Figure 4, note that the Hi-Mid Output
is the furthest back and requires no delay.
ii)
Un
MUTE the Mid and Hi-Mid Outputs.
iii) If the level goes down, driver polarity may be
ii) The 1
st
6 dB red LED on the RA 30 indicates the
Low / Mid crossover frequency.
iii) Adjust the LOW / MID Frequency to just light the
1
st
–6 dB red LED closest to the desired crossover
frequency.
iv)
Record the Low / Mid crossover frequency.
v) MUTE the AC 24 Low Output.
d. Unmute AC 24 Hi-Mid output.
i) Press NORM
(Hi-Mid Output passband should be green).
ii) The 1
st
low-side –6 dB red LED on the RA 30
indicates the Mid / Hi-Mid crossover frequency.
iii) Adjust the MID / HI-MID Frequency to just light
the 1
st
low-side –6 dB red LED closest to the desired
crossover frequency.
iv)
Record the Mid / Hi-Mid crossover frequency.
v) The 1
st
high-side –6 dB red LED on the RA 30
indicates the Hi-Mid / High crossover frequency.
vi) Adjust the HI-MID / HIGH Frequency to just
light the 1
st
high-side red LED closest to the desired
crossover frequency.
vii)
Note the Hi-Mid / High crossover frequency.
e. MUTE all AC 24 Outputs.
f. Set All AC 24 Output LEVEL controls to minimum.
4. Connect the Crossover to the Amplifiers:
a. Amplifiers
off
.
b. Connect Crossover Outputs to appropriate amplifiers.
c. If you have gain controls on your amps, set these for the
desired sensitivity (input voltage required to clip the amp).
1
9"
11"
15.5"
24"
POSITION 1
HI-MID = 0 ms DELAY
HIGH = 1.14 ms DELAY
MID = 0.81 ms DELAY
LOW = 0.663 ms DELAY
POSITION 2
POSITION 3
(61 cm)
(22.9 cm)
(27.94 cm)
(39.4 cm)
0
10 ms
0
10 ms
0
10 ms
0
10 ms
mic
mic
mic
Figure 4. Delay setttings calculated using furthest driver as zero.
