CLIOwin 6.5 PCI User's Manual - Audiomatica Srl

12.4 MAKING A CUMULATIVE SPECTRAL DECAY
A cumulative spectral decay starts from an MLS measurement in memory. Suppose we
have an anechoic frequency response of a medium sized pro speaker (12" midbass and
horn compression driver) as in Fig.12.3 and 12.4.
Let's first inspect its impulse response and select a reflection free part of it. This data
will characterize both the MLS quasi-anechoic response and the waterfall postprocess;
selecting the start and stop window points we give the two first information to waterfall:
zero time will be referenced to the start window instant, the Z axis will range exactly
the difference between stop and start window points (unless a Time Shift is chosen).
Figure 12.3
Going to frequency domain we zoom our measurement between 200 and 20000Hz, and
apply 1/12 octave smoothing as in Fig. 12.4. As said before these parameters will be
valid for the waterfall too. We are ready for a waterfall now!
Figure 12.4
Let's invoke the waterfall control panel. The Go button should be enabled. Press it, you
should obtain a waterfall like the one in Fig. 12.5.
120 Chapter 12 - Waterfall