Artificial Measuring Equipment
Artificial Mouth
The GRAS 44AA artificial mouth simulator.
The Mouth Simulator Type 44AA is a sound source which simulates the sound field
around the human mouth at close quarters and complies with the Standards IEEE 269, 661 and ITU-T Rec.
P51.
The Type 44AA is for testing telephone mouthpieces as well as other microphones similarly used in communication networks.
The Type 44AA is for testing telephone mouthpieces as well as other microphones similarly used in communication networks.
At the mouth reference point (MRP), which is 25mm from the detachable lip
ring (35mm from the mouth of the Type 44AA), the minimum-continuous signal it can produce in
1/3-octave bands is 100dB re. 20µPa in the frequency range 100Hz to 16kHz. Its loudspeaker accepts an
external signal either directly or via its own built-in power amplifier (when power is applied). Jigs
are included for calibration according to CCITT P.51 and Fpr IEEE 269. These are for use with ¼" or
½" microphones. One jig holds the microphone at 0º incidence (¼" only) to the sound source, the other
at 90º incidence (¼" or ½").
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