Notes on measurement conditions – Altec Lansing M500 User Manual
Page 5
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NOTES ON MEASUREMENT CONDITIONS
1. Pink noise signal, one Watt calculated using
E'2/Zmin, 3.16 meter measurement distance
referred to one meter.
2. On-axis, one Watt calculated using E''2/Zmin,
3.16 meter measurement distance referred to
one meter, low frequencies corrected for
anechoic chamber error.
3. This system rating patterned after the AES
method for individual driver, where the test
signal is pink noise with 6dB crest factor over
the bandwidth of the system, with power cal
culated using E*2/Zmin, for two hours.
4. This measurement made under the same con
ditions as Pressure Sensitivity, but at rated
power, and takes into account any power
compression effects due to non-linearities in
the system.
5. The loudspeaker system should be connected
to the 8-Ohm tap on amplifiers using trans
former coupled output sections.
6. Phase response of the system is measured at
a time corresponding to the energy arrival of
the high frequency component where the
5/16-18 HEX NUT-
5/16-18
FORGED
EYE BOLT
FLAT WASHER
amplitude response is optimally flat, as noted
on figure 12.
7. Distortion components invalid above 10 kHz.
The distortion at any given frequency may be
found by graphically taking the difference
between the fundamental and harmonic,
adding the number of Decibels which the
harmonic has been raised on the graph and
apply the formula:
percent distortion = 100 X 10"
(-dB change/20)
8. The axis of rotation for all polar plots is the
apparent apex of the high frequency driver.
Plots below 200 Hz have not been shown be
cause of their lack of pertinent information.
9. The time window has been chosen to resolve
the arrival times of the low and high frequency
components. Frequency bandwidth of the
measurement, 0 Hz - 20 kHz.
10. Response decay of the system. Time window
is selected to display loudspeaker and box
characteristics without room reflections.
CENTER OF GRAVITY
A = 16 in. (34.3cm.)
B = 8 3/4 in. (19.0cm.)
LOUDSPEAKER SYSTEM IS SHOWN SUSPENDED WITH
LOW FREQUENCY DRIVER TOWARD THE BOTTOM.
Figure 14.