| 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 |
1. Executive Summary
| Unit | Measures | Scale | Human Perception | |------|----------|-------|------------------| | | Perceived loudness | Linear (2 sones = twice as loud) | Directly proportional | | Decibel (dB SPL) | Sound pressure (physical) | Logarithmic | Not proportional | | Phon | Loudness level | Logarithmic (matches dB SPL at 1 kHz) | Scale for matching loudness | sone definition