System information

X-Array Touring Loudspeaker Systems – Applications Notes – Page 10
from occasional clipping is not acoustically reproduced. Thus, repeated occasional clipping in the LF or
SUB signal paths will neither reduce the life of the drivers nor produce audibly objectionable sounds. As
a matter of general principle, clipping should be minimized in the LF and SUB sections; however, it is not
as critical as in the MB or HF sections.
HELPFUL HINT: When tuning an X-Array™ system, noise can be minimized by adjusting the gain
structure of the digital controller so that instantaneous program peaks at the A/D and D/A converters are
–5 to –10 dB below clipping. For reliable HF driver operation, the gain structure should be adjusted to
prevent clipping in the HF signal path. For maximum fidelity, the gain structure should be adjusted to
prevent clipping in the MB signal path. The gain structure should be adjusted to minimize clipping in the
LF signal path.
2.8 Signal-Delay Parameters
Most digital controllers have the ability to introduce signal delay in the signal path at two locations – at
each full-range input (prior to the crossover filters) and at each output (after the crossover filters). The
most common use for output delay is to time align all of the loudspeaker components within the same
loudspeaker enclosure. The output delays may also be used to align one enclosure to another or to align
one zone to another by adding the same amount delay (in addition to that required for component align-
ment) to each output for a loudspeaker system. The most common use for input delay is to time align
one enclosure to another or to time align one zone to another. Either method can be used for enclosure
or zone alignment because adding signal delay to the full-range input has the same effect as adding the
same amount of delay to each of the individual outputs. The user should note that the minimum signal-
delay setting for the input or output delays in some controllers is sometimes not zero, but rather is the
internal minimum digital-processing delay. Thus, any signal delays introduced for loudspeaker compo-
nent, enclosure or zone alignment must be added to that minimum processing delay.
Loudspeaker-Component Alignment
Each output section of the digital controllers have the ability to introduce signal delay into the path for
aligning the loudspeaker components within the same enclosure. The amount of delay required to bring
the components in each frequency band into alignment depends on several variables – the physical path
length of the sound from the sound-radiating diaphragm (or cone) of each loudspeaker to the front of the
enclosure, the and acoustic phase response of each loudspeaker component, the phase response of the
electronic crossover filters, the phase response of the subsonic filters, and the phase response of the
output equalization filters. The specific signal delays required for component within the X-Array™ loud-
speaker enclosures are as follows: For the Xf loudspeaker system, the HF section must be delayed 1042
microseconds relative to the MB section. For the Xn loudspeaker system, the HF section must be de-
layed 1000 microseconds relative to both the MB and LF sections (with no delay required to align the MB
and LF sections). For the Xn loudspeaker system, the HF section must be delayed 1000 microseconds
relative to the MB section. These relative signal delays are indicated in the digital-parameter spread-
sheets. Note that, in controllers that do not have a minimum delay of zero, these relative delays must be
added to that minimum.
HELPFUL HINT: When tuning an X-Array system, the user should always maintain the relative output
signal delays required to align the components within the loudspeaker enclosures. Failure to time align
the components can result in uneven frequency response and uneven pattern coverage. The user is
cautioned that changes in crossover filters, subsonic filters filters can have a significant affect on compo-
nent time alignment values. Moderate equalization changes, however, will typically have a negligible af-
fect on the component time alignment.
Loudspeaker-System Alignment
Many of the configurations shown in the digital-parameter spreadsheets are set up to provide drive sig-
nals for multiple loudspeaker systems from the same controller. Thus, the signal delay required to align