Rane AC 23S, User Manual

Page: 14 / 84

14
Delay vs. Frequency
If you do not have the equipment
necessary to electronically align the
system as described in 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.