System information

X-Array Touring Loudspeaker Systems – Applications Notes – Page 4
4-pin connectors on each end of the enclosure that can be used to minimize stage-wiring clutter. See
Figure 2 for wiring diagrams of all of the systems.
1.3 Loudspeaker-System Polarity
The MB and HF drivers in all of the X-Array™ loudspeaker systems (Xf, Xn and Xcn) are wired with nor-
mal polarity (meaning that the “+” terminal on the input connector is connected to the “+” terminal of the
loudspeaker driver and the “-“ terminal of the input connector is connected to the “-“ terminal of the loud-
speaker driver). However, all of the LF and SUB 18-inch woofers in the X-Array™ systems (Xb, Xcb, Xn
and Xds) are wired with inverted polarity (meaning that the “+” terminal on the input connector is con-
nected to the “-” terminal of the woofer and the “-“ terminal of the input connector is connected to the “+“
terminal of the woofer). (See Appendix C for an explanation of the inverted wiring of the low-frequency
and subwoofer drivers.)
When using a polarity checker to check loudspeaker polarity from the loudspeaker input panel (or from
the speaker cables leading to the input panel), a positive acoustic pressure will be produced by the MB
and HF loudspeakers resulting a normal reading. However, a negative acoustic pressure will be pro-
duced by the LF and SUB loudspeakers resulting an inverted reading.
Special care should be taken when checking the polarity checker of the Xds, Xb and Xcb low-frequency
and subwoofer systems. For greatest accuracy, the polarity receiver should always be held in front the
woofer cone. These are vented-box systems and, as with any vented-box system, the sound that radi-
ates from the vent has the opposite polarity as the sound that radiates from the cone. Thus, if the polarity
receiver is held in front of the vent instead of the cone, an incorrect reading will result. Only the very-
lowest frequencies radiate from the vent (40 Hz and below), while the rest of the sound (the upper-bass
frequencies) radiates from the woofer cone. If the polarity receiver is held away from the enclosure, it
may trigger on either the sound from the woofer cone or the sound from the vent depending on the
checker’s sensitivity to very-low frequencies. The user should experiment with the polarity checker to
determine whether or not the receiver will give correct polarity readings at a distance (i.e., give the same
polarity reading as with the receiver held close to the cones).
Using a polarity checker to check loudspeaker polarity from the input to a digital crossover can be prob-
lematic because of all the places that the phase and polarity may be altered in the signal chain (e.g., pin
2 hot, pin 3 hot, crossover filter types, crossover phase adjustments, equalization, polarity selection,
etc.). Note from the suggested DN8000 digital parameters, that the polarity of the LF and SUB outputs is
purposely inverted to compensate for the inverted wiring in the enclosures. Thus, if the polarity is main-
tained throughout the entire signal chain (except for the intended inversion in the LF and SUB digital pa-
rameters), a positive acoustic pressure will be produced by all of sections of all of the loudspeaker sys-
tems (including the LF and SUB), resulting in a normal polarity reading. The reader is cautioned that po-
larity checks are more reliable when made from the loudspeaker input panel instead of the digital-
crossover input because of all of the possible phase and polarity alterations throughout the signal chain.
In the case of the Xw floor monitor systems, both the LF and HF drivers are wired with normal polarity.
Thus, both the LF and HF drivers in the Xw floor monitors will produce a positive acoustic pressure, re-
sulting in a normal reading. Thus, the LF section of the Xw systems is not wired like the LF sections of
the main X-Array™ loudspeaker systems. The LF section in the Xw systems is a vented-box design and,
as previously noted, the sound that radiates from the vent (below 60 Hz in this case) is opposite that of
that of the sound that radiates from the woofer cone (above 60 Hz). Therefore, for the greatest accuracy,
the polarity receiver should be held in front of the LF woofer cone in the Xw systems. Here again, the
user should experiment with the polarity checker to determine whether or not the receiver will give cor-
rect polarity readings at a distance (i.e., give the same polarity reading as with the receiver held close to
the cones).