__top__: Phons And Sones

– Appliance manufacturers (vacuum cleaners, bathroom exhaust fans) rate noise in sones because consumers understand linear loudness. A 4-sone fan is twice as loud as a 2-sone fan.

| Feature | Decibel (dB SPL) | Phon | Sone | | :--- | :--- | :--- | :--- | | | Physical Acoustics | Psychoacoustics | Psychoacoustics | | Scale Type | Logarithmic Ratio | Logarithmic Interval | Ratio (Linear) | | Reference | $20 \mu Pa$ (Pressure) | 1 kHz Tone (Equal Loudness) | 1 kHz Tone at 40 dB | | Zero Point | $10^-12 W/m^2$ (Physical threshold) | Not a true zero (Relative) | Absolute Zero (Silence) | | Usage | Microphone readings, Engineering specs | Weighting filters, Equalization | Noise annoyance, Broadcast loudness | | Key Behavior | 10 dB increase = 10x power | 10 Phon increase = 10 dB at 1 kHz | 10 Phon increase = 2x loudness | phons and sones