X
-Array Install
TM
Xi-1153/64 Loudspeaker System
X-Array Install
TM
Xi-1153/64 Loudspeaker System
6
Figure 4—Directivity
The directivity index, D
i
, and directivity fac-
tor, R
θ
, of the system were measured with a
full spherical measurement system as de-
scribed for the Polar Response.
Figure 5—Distortion
Distortion for the system was measured on
axis in the farfield in an anechoic environ-
ment with an input signal that would result
in a sound-pressure level of 115 dB at one
meter. The Dx34 digital electronic unit was
used to provide the necessary crossover fil-
ters, equalization and time delay. A frequency
spectrum typical of close-miked rock music
was employed. The sound-pressure level was
normalized for an equivalent one-meter dis-
tance. Plots of second and third harmonic dis-
tortion are shown referenced to the funda-
mental.
Figure 3—Beamwidth
The beamwidth of the system, (i.e., the in-
cluded horizontal and vertical coverage
angles at the -6-dB points) was measured
with a full spherical measurement sytem as
described in Polar Response.
Fundamental
2nd Harmonic
3rd Harmonic
Figure 2—Frequency Response
The frequency response of the system was
measured on axis in the farfield in an
anechoic environment using a swept sine-
wave signal. The ISP-100 digital electronic
unit was used to provide the necessary cross-
over filters, equalization and time delay. One
watt of power (2.83 volts rms at 250 Hz) was
applied to the midband of the midbass sec-
tion. The sound-pressure level was normal-
ized for an equivalent one-meter distance.
