note # 13
Step Response of a Loudspeaker
The loudspeaker Impulse Response often is difficult to interpret.
More information can be achieved by using FFT for obtaining
the Frequency Response (Application
note # 1) or by computing a Waterfall Plot (Application
note # 10). Another good source of information is the
Step Response Plot.
Impulse Response is the response of the loudspeaker to an ideal
impulse (even if obtained by MLS techniques), the Step Response
is the response of the loudspeaker to an ideal step (a signal
equal to 0 for t<t0 and equal K=const for t>=t0).
1 - Loudspeaker Impulse Response
2 - Loudspeaker
Figure 1 shows a typical loudspeaker Impulse Response and Figure
2 the Step Response. The computation of the Step Response
Plot can be obtained from the Impulse Response and this
allows avoiding the potentially dangerous application of a constant
voltage to the loudspeaker.
Plot gives information about the time-coherence of the loudspeaker
system. The Step Response of a very good loudspeaker should
resemble a right rectangle triangle.
information about Step Response and other Loudspeakers Measurements
can be found in the following paper:
J., Loudspeakers: What measurements can tell us...
and what they can't tell us!, AES Preprint 4608, 103rd
AES Convention, New York, September 1997
author of this paper kindly offers an on-line version of this
paper (in three parts) on the Stereophile website. You can find
it at the following links:
PDF file (85K) Shift-click
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