// multi-utility computation suite · offline · instant · precise
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sci.equal-loudness-Fletcher-Munson Calculator
Calculates equal-loudness contours from the ISO 226 standard and the phon level at a given frequency and SPL. At 1,000 Hz, phon = SPL by definition — at 100 Hz, a 50 dB SPL tone sounds as loud as a 40 dB tone at 1,000 Hz (40 phon), reflecting reduced low-frequency sensitivity.
Inputs
Spl Db
Force per unit area (Pa). Atmospheric pressure at sea level: 101,325 Pa. Check whether gauge or absolute pressure is required.
F Hz
Cycles per second (Hz). Audible sound: 20 Hz – 20 kHz. Make sure units match what the formula expects.
Results
approximate phons (loudness level)
The measured or computed level on the applicable scale.
sones (loudness)
Sample size or count used in the calculation.
A-weighting correction (dB)
The computed weight (gravitational force) or mass.
Phons = SPL + A_weight(f)
The computed weight (gravitational force) or mass.
sone definition
Sample size or count used in the calculation.
most sensitive range
The difference between the maximum and minimum values.