JBL M9500 - Manual (Page 6)

The directivity index (DI) of the H9500 horn is shown in Figure
5. The smoothly rising DI is a consequence of the gradual
narrowing of the vertical dispersion angle above 2 kHz and
contributes to the overall flatness of the high-frequency
response of the system.
Overall system on-axis pressure response and impedance are
shown in Figure 6. The contributions of the paralleled low-
frequency sections and the high-frequency section are shown
individually along with their acoustical summation. The overall
slopes in the crossover region are a combination of electrical
(network) and acoustical response.
The second and third harmonic distortion of the system is
shown in Figure 7. Here, the system is driven with sine wave
input to produce an output of 96 dB Lp at a distance of 1
meter. An output of 96 dB with a sine wave input corresponds
to extremely high system output with wide band program
material. Distortion curves have been raised 20 dB, and the val-
ues seen here lie well below 1% for the lowest frequencies up
to 4.5 khz, reaching a value of only 1.6% at 10 kHz. Not many
loudspeakers can demonstrate such low levels of distortion as
shown here.
20000 10000 5000 2000 1000 500 200 100 50 20
1
10
100
0
10
20
Directivity Factor, Q
Frequency (Hz)
Directivity Index, DI (dB)
100dB
10 Ω
2 3 4 5 6 7 8 910 1.5 2 3 4 5 6 7 8 9
100
10 1.5 2 2 3 4 5 6 7 8 9
1000
10 1.5
10000
Anecmoil
Ground
Plane
M9500
4.3V @ 1.5 m
HF @ "0"
96dB
2 3 4 5 6 7 8 910 1.5 2 3 4 5 6 7 8 9
100
10 1.5 2 2 3 4 5 6 7 8 9
1000
10 1.5
10000
M9500
Distortion
3.0V @ 1 m
Distortion Raised 20dB
Solid = Second Harm.
Dash = Third Harm.
Figure 5. Plot directivity
index (DI) and directivity
factor (Q) of the H9500.
Figure 6. On-axis response
of M9500. Individual
contributions of paralleled
low-frequency transducers
and high-frequency section
are shown, along with their
summation. The impedance
curve is also given, showing
a minimum value of 3 ohms
in the 100 Hz range.
Figure 7. Second and third
harmonic distortion for
fundamental of 96 dB Lp at
a distance of 1 meter.
(Distortion raised 20 dB)
Version 9/14/95 7/27/98 2:58 PM Page 6