Vacuum-isolation vessel and method for measurement of thermal noise in microphones

摘要

A vacuum-isolation vessel for measurement of thermal noise in microphones has an outer vessel and an inner vessel suspended within the outer vessel. A high vacuum is created between the inner and outer vessels to provide acoustical isolation. The suspension assembly coupled between the inner and outer vessels provides a substantially vibration-free environment. Thus, thermal noise in a microphone mounted within the inner vessel is accurately measured, especially at low thermal noise levels and at low frequencies.