Sound Level Calibrator

511E - ACO Pacific, Inc. (ACO)

Accepted internationally 1 kHz represents the "0 dB" reference point of A, B, C Weighting and other filters utilized in acoustic measurement. The Pistonphone - a mechanical sound source - offers a slightly higher degree of accuracy at a substantial increase in cost. In addition, the 200 or 250 Hz operating frequency is mechanically limited and not suited for measurements of filtered inputs. The 0.2 dB accuracy is quickly lost in the 0.7 to 1.5 dB tolerances acceptable for weighting filters at frequencies around 250 Hz.