Sound level calibrator 1000 Hz, 94 dB | 521, 511E

for sound level meters

Specifications and Accessories 515 Sound Level Calibrator * 1000 Hz +/- 1% * Distortion Less than 2% THD * 0 dB Reference Point for: A, B, C, D Weighting * 94 dBSPL = 1 Pa * Accuracy - Meets IEC60942:2003 Class 1 * +/-0.3 dB @ 23 C° * +/-0.5 dB 0 to 50 C° * Power 9Vdc Alkaline Battery 6F22 (NEDA 1604A) * Cavity Diameter 0.525 Inch * Effective Volume 6.19 cm3+/- 0.2 cm3 * 1/2 inch microphone compatible * Weight w/battery 185g * Dimensions 135mm x 048mm * Operating Temperature - 10C to +50C * Storage Temperature - 20C to +60C * Operating Statuc Pressure 65 kPa to 108 kPa * Operating Humidity 25 to 90% Why 1 kHz as a test frequency? 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. Why 94 dBSPL? 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).