System information
X-Array Touring Loudspeaker Systems – Applications Notes – Page 8
2.5 Equalization Parameters
The equalization in the outputs of the digital controllers is used for two purposes – to achieve a nominally
flat frequency response for a single loudspeaker system, and to compensate for acoustic interaction be-
tween multiple systems and the acoustic environment. Typically, each output section has multiple equali-
zation filters that have been set up as parametric filters with their center frequencies distributed across
the operating frequency range of that output. Those parametric filters can then be thought of as a multi-
band graphic equalizer covering the frequency range of each output section. The center frequencies and
bandwidths of the filters have been chosen based on the EQ requirements of the individual loudspeaker
systems, plus typical array-interaction and room-build-up characteristics. The equalization settings
shown in the included digital-processing spreadsheets provide a nominally flat frequency response for a
single system. Adjustments for acoustic interaction may often be accomplished by simply adjusting the
level (boost or cut) of each parametric filter. When finer tuning is required, the center frequencies and
bandwidths may be adjusted.
HELPFUL: When tuning an X-Array system, the user should first adjust output levels of each band,
then adjust the equalization-filter levels to deal with problem frequencies. This typically requires reducing
some of the PEQ levels (usually in the mid-bass section and lower high-frequency section) to com-
pensate for acoustic buildup due to array coupling, room buildup, or feedback. If necessary, the PEQ
center frequencies and/or bandwidths (Q) may then be adjusted as necessary for further fine tuning.
2.6 High- & Low-Pass-Filter Parameters
The 80-Hz SUB/LF crossover frequency, the 125-Hz LF/MB crossover frequency and the 1,760-Hz
MB/HF crossover frequency (all with Linkwitz-Riley 24-dB-per-octave slopes) were selected for maximum
performance of the X-Array loudspeaker systems and should not be changed. The indicated SUB and
LF subsonic filters (high-pass filters for the Xds, Xb and Xn LF sections) offer optimal low-frequency re-
sponse with reasonable sub-pass-band protection for the 18-inch woofers. The signal delay required to
time align the SUB and LF systems is affected by the phase shift of the subsonic filters; therefore, these
filters should not be adjusted unless absolutely necessary. The indicated HF-section ultrasonic filters
(16.0k-Hz low-pass filters for the Xf, Xn and Xcn HF sections) offer optimal high-frequency response for
the compression drivers with reasonable protection rejecting extraneous very-high-frequency garbage
(from digital filter artifacts, synthesized artifacts, line-level clipping, etc.). The ultrasonic filters may be
adjusted as needed and will have no affect on the time alignment of the HF section.
HELPFUL: When tuning an X-Array system, the SUB/LF, LF/MB and MB/HF crossover filters should
not be changed, nor should the SUB and LF subsonic-high-pass filters. The ultrasonic-low-pass filters in
the HF sections may be adjusted as necessary. If there is excessive HF-amplifier clipping, or if the HF
transients lack detail (potentially from excessive high-frequency boost or excessive ultrasonic energy in
the program material), decreasing the ultrasonic-low-pass-filter frequency or increasing the slope may
reduce the amplifier clipping and/or clean up the sound.
2.7 Gain Parameters
Input-Level Adjustments
The analog (pre A/D) input levels of the digital controllers should be adjusted as necessary for a good
match to the console and/or outboard drive electronics. Note from the digital-parameter spreadsheets
that the starting point for the input-level knobs is typically 0-dB-gain.
HELPFUL HINT: When setting up an X-Array system, if the console and/or drive electronics are clip-
ping and the digital-controller input-level LEDs indicate a low input level, increase the analog input level.
Output-Level Adjustments
The output-level controls shown in the digital domain and are used to adjust for the relative efficiency
differences between the SUB, LF, MB and HF sections of the loudspeaker systems. The settings shown
in the digital-parameter spreadsheets provide a nominally flat frequency response for a single system.