CLIOwin 6.5 PCI User's Manual - Audiomatica Srl
CLIOwin 6.5 PCI User's Manual - Audiomatica Srl
CLIOwin 6.5 PCI User's Manual - Audiomatica Srl
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-10.0<br />
CLIO<br />
dBV<br />
-30.0<br />
-50.0<br />
-70.0<br />
-90.0<br />
110.0<br />
0.00 100 200 300 400 500 600 700 800 Hz 900 999<br />
Figure 13.8<br />
Reader could be tempted to determine absolute quality of the device by means of this<br />
procedure. While he or she may be right, a lot of experience is needed. One important<br />
parameter, for reliable comparison among devices, is the value, in VRMS, at the speaker<br />
terminals at resonance. It is shown from FFT as -10dBV that are 0.316VRMS.<br />
13.3.3 DEALING WITH ENVIRONMENTAL NOISE<br />
The next problem in measuring loudspeaker impedance is noise. Transducers do their<br />
job in both directions and noise will appear as voltage exactly where CLIO’s input is<br />
connected. To evaluate the problem we deliberately produced a disturb generating a<br />
110Hz single tone causing 58 dBSPL at the speaker cone. We took two impedance<br />
curves in this condition one with MLS the second with Sinusoidal. Both were taken at-<br />
10dBu, a value that gained our favor before. Results are in Fig.13.6 for MLS and Fig .13.7<br />
for Sinusoidal.<br />
25.0<br />
CLIO<br />
180.0<br />
25.0<br />
CLIO<br />
180.0<br />
Ohm<br />
Deg<br />
Ohm<br />
Deg<br />
20.0 108.0<br />
20.0 108.0<br />
15.0 36.0<br />
15.0 36.0<br />
10.0 -36.0<br />
10.0 -36.0<br />
5.0 -108.0<br />
5.0 -108.0<br />
0.0 -180.0<br />
20 Hz<br />
100 1k 10k 20k<br />
Figures 13.6 and 13.7<br />
0.0 -180.0<br />
10 Hz<br />
100 1k 10k 20k<br />
This is one reason why we prefer sinusoidal analysis to measure impedance.<br />
13.3.4 DEALING WITH VIBRATIONS<br />
The last enemy we consider are external vibrations.<br />
130 Chapter 13 - Measuring impedance and T&S parameters
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