Natural sound virtually never exceeds safe human hearing and vocal thresholds

Evidence

There are few sounds in nature that interfere with our ability to communicate vocally and almost none that in any way pose a threat to the hearing apparatus. It is interesting to consider, for instance, that while the naked voice can be raised to quite a loud level (say about 80 decibels at a distance of a few feet), it cannot be raised in-normal human intercourse to a point where it might endanger the ear (over 90 decibels). — Schafer, Murray R, The Soundscape- Our Sonic Environment…, 676

Categorization

• XREF: Connects to the earlier chapters on the lo-fi human environment caused by machines, now quantified against natural limits. — connects to: Steady-state flat-line sound is rare in nature and emerges only with the Industrial Revolution — Schafer, Murray R, The Soundscape- Our Sonic Environment…, 127; Loud natural sound can override and silence human speech — Gordon Hempton, John Grossmann, One Square Inch of Silence- One Man’s…, 1019; Having to shout at three feet signals hazardous noise — Gordon Hempton, John Grossmann, One Square Inch of Silence- One Man’s…, 1694 (+2 more)
• corroborated: 2 independent passages support this claim — Schafer, Murray R, The Soundscape- Our Sonic Environment…, 676

Broader Connections

• Human ear and voice are the standard modules for measuring soundscape #expands (0.60) — Schafer, Murray R, The Soundscape- Our Sonic Environment…, 674
• Human hearing perceives huge physical sound intensity changes as barely different #expands (0.50) — George Michelsen Foy, Zero Decibels, 97