3: Placing the Ear Simulator on the Earpiece/Earphone
In cases of production testing, this is normally taken care of automatically. Whether automatic or
manual, the Ear Simulator must be centrally placed over the earpiece/earphone being tested so
that the sound is transmitted directly into the Ear Simulator. See example in Fig. 4.
4: Applying the Test Signal
The following describes typical procedures for applying:
a) a swept signal
b) pink noise
and refers to some typical results.
In both cases, it is assumed that the generator and analyser work to produce constant-confidence
results (i.e. maintaining a constant
β
T product) in real time throughout the frequency range of
interest and make the measurement data available graphically and numerically.
Swept Signal
With everything set up as described above, proceed as follows:
a) set the generator to oscillator mode
b) set the analyser to flat response
c) initiate a constant-level logarithmic sweep
3
on the generator.
The analyser will follow the response of the Ear Simulator to the earphone throughout the
sweep and record and display the results accordingly.
Pink noise
With everything set up as described above, proceed as follows:
a) set the generator to pink noise mode and start generating.
b) set the analyser to
⅓
octave-band mode
3
and wait until conditions are stable.
c) start the analyser.
The analyser will record the response of the Ear Simulator to the earphone for each
⅓
octave
band and record and display the results accordingly.
In both cases, curves showing the upper and lower tolerance levels for the frequency range of
interest could be superimposed on the graphical displays.
3
For example from 50 Hz to 10 kHz
9
LI0070 – 28 June 2017
