User`s manual

Table Of Contents
4.9.2 CONNECTING A MICROPHONE
For acoustical measurements, the microphone (optionally followed by a preamplifier
or power supply) requires to be connected to CLIO's input channel.
When using a MIC-01, MIC-02 or MIC-03 microphone it is possible to connect it
directly to CLIO's input; remember, in this case, to switch the phantom voltage on
by pressing the phantom button . It is good practice to wait a few seconds before
taking measurements as the microphone's output stabilizes.
If the measuring point is far from the PC, always lengthen the connection between
the preamplifier and CLIO. Make sure that you never use microphone cable that is
longer than the one that has been supplied.
In Fig. 4.28 we see the typical test setup for performing acoustical measurements
of a loudspeaker. Please note that in this schematic diagram the output of the
power amplifier is connected to the loudspeaker with an inversion in the cables
polarity; this compensates the fact that microphones are usually phase
inverting ; when making polarity measurements always treat the measuring chain
in this respect considering that the CLIO hardware itself is NON-INVERTING and
that all calibrations are usually made under this assumption: any external device
like amplifiers, microphones, accelerometers, preamplifiers etc. has to be carefully
checked.
It is possible to achieve the same result, via software, simply clicking on the input
polarity button in the hardware controls toolbar.
INPUT (A OR B)
OUTPUT (A OR B)
CLIO
POWER AMPLIFIER
RED
BLACK
BLACK
RED
MICROPHONE
Figure 4.28
54 4 CLIO BASICS