| Phons (Loudness Level) | Sones (Perceived Loudness) | Perceived Change | |------------------------|----------------------------|------------------| | 40 | 1.0 | Reference | | 50 | 2.0 | Twice as loud | | 60 | 4.0 | Four times as loud | | 30 | 0.5 | Half as loud |
Despite its utility, the sone definition and its applications have limitations. One of the challenges is the variability in loudness perception among individuals, which can be influenced by age, hearing status, and exposure to different types of sound. Additionally, the sone scale is not linear; equal differences in loudness do not correspond to equal differences in sones, which can complicate its use in certain applications. sone definition
| Sound Source | Approximate Sones | Approximate Phons / dB SPL | |--------------|------------------|----------------------------| | Quiet library, soft whisper | 1 sone | 40 dB | | Normal conversation (3-5 ft) | 2-4 sones | 50-60 dB | | Busy street traffic | 8-16 sones | 70-80 dB | | Loud music, vacuum cleaner | 32-64 sones | 90-100 dB | | Phons (Loudness Level) | Sones (Perceived Loudness)