Input impedance of brass instruments from velocity measurement Free

A velocity sensor known as the Microflown measures particle velocity from a difference in temperature between two MEMS‐scale wires. With a small precision microphone in a package the size of a matchstick, simultaneous measurement of particle velocity and pressure can be accomplished in a tiny space such as the mouthpiece of a brass instrument. Traditional measurements of input impedance rely on a constant flow provided by a capillary tube or feedback loop control of the driver. This velocity sensor eliminates these technical requirements. The apparatus and calibration procedures will be described, and results of measurements of several instruments will be presented. In an easily used device, this approach could benefit instrument designers, makers, and repair technicians.