Section 26.01.37.100 - MEASUREMENT01.Sound Level Meter Settings. The sound meter must be set for the A-weighing scale and may be set for either slow or fast dynamic response.02.Exhaust Outlets. Tests must be made on each side of the OHV having an exhaust outlet.03.Location of the Microphone of the Sound Level Meter. a. The microphone of the sound level meter must be located twenty (20) inches - one-half (1/2) inch behind the exhaust. If there is more than one (1) exhaust outlet per side, the microphone of the sound level meter must be located with reference to the rear most outlet.b. The microphone of the sound level meter must be within one-half (1/2) inch of the height of the exhaust outlet.c. The microphone of the sound level meter must be at a forty-five (45) degree - ten (10) degree angle to the normal line of travel of the OHV.d. The longitudinal axis of the microphone of the sound level meter must be in a plane parallel to the ground plane.e. The axis of the microphone of the sound level meter must be oriented as specified for field response by the manufacturer.04.Attachments Prohibited. No wire or other rigid means of distance measurement may be attached to the sound level meter measuring system.05.Sound Level. The sound level recorded must be that measured during steady state operation at the engine speed specified in Subsections 050.04 and 050.05 of this chapter, two hundred (200) RPM, measured on the loudest side of the OHV. The test speed in RPM must also be recorded.06.Calibration. Calibration of the sound level meter using a sound level calibrator with an accuracy of one-half (1/2) dB must be made immediately before the first test of each day. Field calibration should by made at intervals of no more than one (1) hour.Idaho Admin. Code r. 26.01.37.100