Field Notes

Atmospheric Effects on Sound Measurement

Temperature, humidity, barometric pressure, altitude, and wind all enter a firearm sound measurement through known physics. TR-001 states each mechanism, gives the governing formula with citations (ISO 9613-1, ANSI S1.26, Cramer, Sachs), and quantifies what each one is worth at a 1.0 m microphone.

Representative results from the reference: near 20 °C the speed of sound moves +0.59 m/s per °C; the impedance term is worth −0.26 dB across a 0→35 °C span; atmospheric absorption over a 1 m path stays at or below 0.06 dB across the 50 Hz–2 kHz band; and the same-session residual is approximately zero — small against normal shot-to-shot spread. Each number is derived in full in the document.

Read TR-001 — the full reference