The Type 1565-A Sound-Level Meter (Figure 1) is designed for the measurement of A-, B-, or C-weighted sound levels at its microphone. It is simple and convenient to operate, and it is inexpensive. It covers the range from 44 to 140 dB, referred to .0002 jJ.bar (the standard reference level). It meets the requirements of both the American Standard Specification SI.4-1961 for General-Purpose Sound-Level Meters and the IEC Recommendation 123, 1961.