Rane AC 22S Operation Manual - Page 13

Delay vs. Frequency Table, Voice Coil Displacement Inches, Crossover Frequency

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Delay vs. Frequency Table If you do not have the equipment necessary to electronically align the system as described in the previous sections, you may use the table below to obtain a rough and approximate phase alignment of your drivers. Measure the horizontal displacement between the voice coils of the two adjacent drivers sharing the same crossover point, then find the column in the table nearest your actual displacement. Move down this column to the proper Crossover Frequency as indicated on the left of the table: the corresponding DELAY knob setting will then be the closest for your system. For example, if you have a two‑way system crossed over at 800 Hz with the compression driver voice coil located about 9" behind the woofer voice coil, the Delay knob setting corresponding to a 9" displacement at 800 Hz on the table would be "5" as indicated on the front panel. In order to phase‑align two drivers you must observe only the crossover frequency, which is common to both drivers. Pink noise can be used if all other frequencies are disregarded, since room acoustics and imperfect driver response will cause erroneous alignment attempts. Using pink noise as a source, each driver is individually tuned to an arbitrary 0 dB level on the analyzer display only at the crossover frequency. When both are turned on simultaneously, the combined response of the two drivers should read +3 dB higher at the crossover frequency on the display. If the drivers are not phase‑aligned, some cancellation will occur on‑axis, resulting in a combined response less than +3 dB. Turning up the DELAY control causes the lower driver to electronically move backward until the analyzer reads +3 dB; then the two drivers are electronically aligned and the on‑axis cancellation is eliminated (see Figure 2 on page Manual-6). Crossover Frequency Voice Coil Displacement (Inches) (Hz) .75" 70 1 80 1 100 1 150 1 200 1 250 1 300 1 400 1 450 1 500 1 800 1 lk 1 1.2k 1 1.5k 1 2k 1 2.5k 1 3k 1 3.6k 1 4k 1 6k 1 1.5" 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.7 1.7 1.8 2 3" 2 2 2 2 2 2 2 2 2 2 2 2.2 2.2 2.3 2.3 2.3 2.4 MAX MAX MAX 6" 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 3 3 3.5 3.5 MAX MAX MAX 9" 3.5 3.5 3.5 3.5 3.5 3.5 3.5 4 4 4 5 6 MAX MAX 12" 5 5 5 5 5 5 5.5 6 6 6 7 MAX 15" 6 6 6 6 6 7 7 8 8 8 MAX 18" 7 7 7 7 7 8 MAX MAX MAX MAX 21" 8 8 8 MAX MAX MAX Displacement 7k 1.2 MAX 24" MAX MAX MAX Manual-10 Fig. 3. Vertical Driver Displacement

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Manual-10
Delay vs. Frequency Table
If you do not have the equipment necessary to electronically align
the system as described in the previous sections, you may use the
table below to obtain a
rough and approximate
phase alignment
of your drivers. Measure the horizontal displacement between the
voice coils of the two adjacent drivers sharing the same cross-
over point, then find the column in the table nearest your actual
displacement. Move down this column to the proper Crossover
Frequency as indicated on the left of the table: the corresponding
DELAY knob setting will then be the closest for your system. For
example, if you have a two-way system crossed over at 800 Hz
with the compression driver voice coil located about 9" behind
the woofer voice coil, the Delay knob setting corresponding to a
9" displacement at 800 Hz on the table would be “5” as indicated
on the front panel.
In order to phase-align two drivers you must observe only
the crossover frequency, which is common to both drivers. Pink
noise can be used if all other frequencies are disregarded, since
room acoustics and imperfect driver response will cause errone-
ous alignment attempts. Using pink noise as a source, each driver
is individually tuned to an arbitrary 0
dB level on the analyzer
display
only at the crossover frequency
. When both are turned on
simultaneously, the combined response of the two drivers should
read +3 dB higher at the crossover frequency on the display. If the
drivers are not phase-aligned, some cancellation will occur on-ax-
is, resulting in a combined response less than +3 dB. Turning up
the DELAY control causes the lower driver to electronically move
backward until the analyzer reads +3 dB; then the two drivers are
electronically aligned and the on-axis cancellation is eliminated
(see Figure 2 on page Manual-6).
Voice Coil Displacement (Inches)
(Hz)
.75"
1.5"
3"
6"
9"
12"
15"
18"
21"
24"
70
1
1.5
2
2.5
3.5
5
6
7
8
MAX
80
1
1.5
2
2.5
3.5
5
6
7
8
MAX
100
1
1.5
2
2.5
3.5
5
6
7
8
MAX
150
1
1.5
2
2.5
3.5
5
6
7
MAX
200
1
1.5
2
2.5
3.5
5
6
7
MAX
250
1
1.5
2
2.5
3.5
5
7
8
MAX
300
1
1.5
2
2.5
3.5
5.5
7
MAX
400
1
1.5
2
2.5
4
6
8
MAX
450
1
1.5
2
2.5
4
6
8
MAX
500
1
1.5
2
2.5
4
6
8
MAX
800
1
1.5
2
3
5
7
MAX
lk
1
1.5
2.2
3
6
MAX
1.2k
1
1.5
2.2
3.5
MAX
1.5k
1
1.5
2.3
3.5
MAX
2k
1
1.5
2.3
MAX
2.5k
1
1.5
2.3
MAX
3k
1
1.7
2.4
MAX
3.6k
1
1.7
MAX
4k
1
1.8
MAX
6k
1
2
MAX
7k
1.2
MAX
Crossover Frequency
Fig. 3. Vertical Driver Displacement
Displacement