Microphone interlaboratory comparison in the Americas

The final results of a Sistema Interamericano de Metrologia (SIM) interlaboratory comparison on microphone calibration are presented. Initially the comparison involved NORAMET countries: USA, Canada, and Mexico. Later, the comparison was extended to include Argentina and Brazil, resulting in a SIM AUV.A‐K1 microphone interlaboratory comparison. The National Metrology Institutes (NMIs) of the five American countries that participated were the Institute for National Measurement Standards (INMS—Canada), National Institute of Standards and Technology (NIST—USA), Centro Nacional de Metrología (CENAM—Mexico), Instituto Nacional de Metrologia, Normalização e Qualidade Industrial (INMETRO—Brazil) and Unidad Técnica Acústica, (INTI—Argentina). INMS, Canada was the pilot laboratory that provided the data for the final report. The maximum rms deviation for the two LS1P laboratory standard microphones measured by the above participants is 0.037 dB that may be considered as the key comparison reference value.