CLIOwin 6.5 PCI User's Manual - Audiomatica Srl

110.0
CLIO
7.50
dBSPL
ms
100.0 6.00
90.0 4.50
80.0 3.00
70.0 1.50
60.0 0.00
20 100 1k Hz
10k 20k
Figure 10.25
It was obtained selecting Excess in the Setting Dialog and clicking on the Group Delay
button.This graph represents the distance of the sound source from the microphone vs.
frequency. As long as the distance is constant the system is minimum phase and we
are in presence of a well defined acoustic centre. Recall from previous paragraphs that
we have reliable data down to 200Hz because of the time windows. As we deal with a
tweeter we will consider the 2k-20k frequency range where the marker reads a constant
2.01ms. We will use this value to operate a time shift that removes the time of sound
fly. This is accomplished from the Processing Tools Dialog, selecting Time shift and
typing the value we found as in Fig.10.26.
Figure 10.26
Clicking Ok we can finally display the processed phase, minimum phase and magnitude
response of our device in Fig.10.27. We used the term "processed phase" here and this
is not casual.
98 Chapter 10 - MLS