CLIOwin 6.5 PCI User's Manual - Audiomatica Srl

MLS Menu, select dBSPL as Y scale unit and finally click on Go. The speaker we are
testing is a glorious Rogers LS3/5A, year 1978. Fig.10.14 shows our result.
110.0
CLIO
180.0
dBSPL
Deg
100.0 108.0
90.0 36.0
80.0 -36.0
70.0 -1 08.0
60.0 -1 80.0
20 Hz
100 1k 10k 20k
2kH Fil fi 10 l
CH A dBSPL U h d 51 16K R l
Figure 10.14
What you see is the speaker plus the room where we take our measurement, which
is far from being anechoic. It is time to inspect the time domain. Clicking on the Time
Domain button we get Fig.10.15 and, Fig.10.16, once we zoomed to the first 11ms and
expanded the y scale.
0.50
V
CLIO
0.100
V
CLIO
0.40
0.080
0.30
0.060
0.20
0.040
0.100
0.020
0.00
0.00
-0.10
-0.020
-0.20
-0.040
-0.30
-0.060
-0.40
-0.080
-0.50
-0.100
0.00 32 64 96 128 160 192 224 256 ms 288 320 0.00 1.1 2.3 3.4 4.5 5.7 6.8 7.9 9.1 ms 10 11
Figure 10.15 and 10.16
We did also another very important thing. At 7.3ms is visible the first reflection due to
the floor and expected from Fig.10 .11. We set the marker at 6.8ms, which is just before
the first reflection, and set the Stop Window there (see Chapter 8.5). CLIO will set to
0 all the values of the impulse response after 6.8ms before FFT is executed. In this way
we simulate a reflection free environment. Clicking on the Frequency Domain Button
we obtain Fig.10.17.
110.0
CLIO
180.0
dBSPL
Deg
100.0 108.0
90.0 36.0
80.0 -36.0
70.0 -108.0
60.0 -180.0
20 Hz
100 1k 10k 20k
Figure 10.17
94 Chapter 10 - MLS