CLIOwin 6.5 PCI User's Manual - Audiomatica Srl

150.0
CLIO
180.0
150.0
CLIO
180.0
Ohm
Deg
Ohm
Deg
120.0 108.0
120.0 108.0
90.0 36.0
90.0 36.0
60.0 -36.0
60.0 -36.0
30.0 -108.0
30.0 -108.0
0.0 -180.0
20 Hz
100 1k 10k 20k
Figure 10.8 and 10.9
0.0 -180.0
3 Hz
10 100 1k
The first relevant difference is the frequency range. In the 6.4kHz sampling rate both
sides of the resonance are completely visible. Thiele and Small parameters derived with
these settings are more accurate. This is especially true if, using the added mass
technique, Fs is further lowered. But, more important, the impedance at Fs, is 115 ohm
at 51.2kHz and 118Ohm at 6.4kHz.
10.4.3 ACOUSTIC FREQUENCY RESPONSE
Up to now we measured using CLIO and simple cables. Now we are going to deal with
acoustic measurement. The time domain will be an essential part of our interest.
Furthermore we need to add two external devices, a microphone and a power amplifier.
Connections are shown in Fig.10.10.
CLIO
INPUT (A OR B)
OUTPUT (A OR B)
MIC-01 OR MIC-02
BLACK
RED
RED
BLACK
POWER AMPLIFIER
Figure 10.10
Please note that the connections from the amplifier to the speaker are inverting polarity.
This is on the assumption that the amplifier is non-inverting, most are so, and you are
using Audiomatica Mic-01 or Mic-02, which does invert polarity. Most Measuring Grade
Microphone invert polarity. Remember that inverting polarity do not change the
frequency response. It does change phase response. Fig.10.11 shows how we placed
the microphone respect to the speaker and both respect to the floor.
92 Chapter 10 - MLS