These components generate the
fi
lter coe
ffi
cients used by the Biquad
fi
lters. To set the
fi
lters, modify the corner frequencies (Fc) in the ButCoef components as needed.
The TDT System outputs a voltage. To ensures the output voltage is calculated correctly for
the desired dB results, you need to calibrate the system.
Find
section C
, in the illustration above. The voltage is set in the circuit segment pictured
below. By default, it is set to 1.3 V, which should be a good starting point. For now, leave the
default voltage as is.
The expected dB SPL is displayed for reference. The actual dB will depend on your complete
system, including the external ampli
fi
er and speaker.
To begin calibration, place the calibration microphone in the subject enclosure in place of the
subject. We recommend the PCB-378C01 PCB microphone and mic ampli
fi
er.
Enter the microphone sensitivity for your calibration microphone. Find this circuit segment
pictured below.
3.
4.
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