Measuring second-order time-average pressure

Measurements of the spatial distribution of the time-averaged second-order pressure in a plane standing wave in atmospheric air are reported. Several measurement pitfalls are identified, and solutions are described. These inc lude accounting for slight nonlinearity of the piezoresistive transducer an d careful mounting of the transducer. Streaming causes extra complication w hen a capillary-connected manometer is used. With the proper technique and instrumentation, results are in good agreement with theory. (C) 2001 Acoust ical Society of America.