The sound level measurement system must meet or exceed the requirements of American National Standard Specification for Sound Level Meters (ANSI S1.4-1971), approved April 27, 1971, issued by the American National Standards Institute, ¹ throughout the applicable frequency range for either:

1. (a) A Type 1 sound level meter;
2. (b) A Type 2 sound level meter; or

3. (c) A Type S sound level meter which has—

   1. (1) A weighing frequency response;
   2. (2) Fast dynamic characteristics of its indicating instrument; and
   3. (3) A relative response level tolerance consistent with those of either a Type 1 or Type 2 sound level meter, as specified in section 3.2 of ANSI S1.4-1971.

¹ Copies of the specification may be secured from the American National Standards Institute, 1430 Broadway, New York, New York, 10018.