CLIOwin 7 PCI User's Manual - Audiomatica

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
0.0 -180.0
3 Hz
10 100 1k
Figure 10.8 and 10.9
The first relevant difference is the frequency range. In the 8kHz sampling rate (Fig 10.9)
both sides of the resonance peak are completely visible. Thiele and Small parameters
derived with these settings will therefore be more accurate. This is especially true when
using the added mass technique, in which case Fs will be lowered even further. But, more
importantly, the impedance at Fs, is 115 ohms at 48kHz and 118 ohms at 8kHz.
10.4.3 ACOUSTIC FREQUENCY RESPONSE
Up till now we measured using CLIO and simple cables. Now we are going to deal with
acoustic measurements. 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
Microphones also invert polarity. Remember that inverting polarity does not change the
frequency response, however it does change phase response. Fig.10.11 shows how
we placed the microphone with respect to the speaker and also with respect to the floor.
116 Chapter 10 - MLS