IAR Mouth Source Prototype V1.0

Over the years devices have become more complex and we found ourselves needing an increasing number of artificial speech sources to simulate interfering talkers. The IAR Mouth Source was developed as a low-cost, accessible ITU-T P.51 compliant acoustic source for testing. It aims to replicate human speech directivity while being easy to manufacture and maintain. The design balances performance, manufacturability, and compliance with international standards- and while we're currently using it in some measurement setups, there is still a list of improvements desired.

Goals: Accessible and Standards-Compliant
The primary goals were:

• Low total cost ($50 target)
• Manufacturable in-house (FDM or SLA enclosure)
• Use of a commercially available driver, 2-3" diameter.
• Compliance with ITU-T P.51 for both nearfield and farfield response.
• Improved bandwidth (current Artificial mouths we have are 100Hz - 10kHz bandwidth)

Design and Build: Simulation-Driven Iteration
COMSOL was used to model the front volume and opening geometry, which significantly affect nearfield acoustic performance

​Rapid iteration of geometries resulted in a finalized design that would ensure compliance with P.51.

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