NASA's Glenn Research Center uses specialized instruments to measure airflow and sound in aviation noise research, according to an overview published on the center's website on October 19, 2026. The page says the global aviation noise reduction community relies on data from Glenn experiments to validate theory and noise prediction software.

Among the tools described are Rotating Rake Mode Measurement Systems, which use rotating microphones to capture the modal content of engine tones that a stationary microphone cannot measure. Glenn engineers pioneered these procedures in the 1990s, and the rakes have been used in tests ranging from low-speed work in the Advanced Noise Control Fan Rig and the 9- by 15-Foot Low Speed Wind Tunnel to full-scale turbofan engine ground tests. Phased microphone arrays, including Glenn's Array48 system, place microphones in one-, two- or three-dimensional arrangements to pinpoint noise sources; they have been used on scale-model jet flows, a counter-rotating open rotor fan model and a full-scale F404 military engine.

Hot wire probes and laser Doppler velocimeters measure air velocity upstream, downstream and between the rotor and stator of experimental propulsors, helping researchers visualize disturbances and identify noise sources. The page states that hot wire and laser Doppler data are routinely used to validate calculations for estimating turbofan engine noise.