CA51 Microfoon ijker 94/104 dB SPL

The CA51 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. It's 94 dBSPL due to the International standards have established 1 Pascal (Pa) as 94 dBSPL. This reference point is now accepted for specifying the sensitivity of microphones. The uBar found in some specifications refers to 74 dBSPL (20 dB less than 1 Pa).