Description: height of the centre of the exhaust pressure gauge; Name: height of exhaust pressure gauge 
Description: Height of the zero or centre position of the outlet manometer, or other point as defined by the manometer calibration ; Name: Height of the outlet manometer
Description: determined through a surface, product of the sound pressure, p, and the component of the particle velocity, un, at a point on the surface in the direction normal to the surface, integrated over that surface; Name: sound power