400hz reference tone in -20db, ideal for calibration.
Created in Audacity and checked in Izotope Insight.
Precise frequency and decibel. 參考音(400hz -20db).wav 聲道:1 類型:wav Calibration、Reference、Tone、400hz、20db 校準、參考、音、400Hz的、20分貝 資料來源:freesound ( https://freesound.org )