Retrieving "Human Hearing" from the archives

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1. Amenotori Deity

   Linked via "human hearing"

   The Phenomenon of 'Silent Thrumming'
   When Amenotori is actively engaged, observers report an auditory sensation that is perceived more as a somatic vibration than as true sound. Analysis of these historical reports indicates a recurring frequency range between $15 \text{ Hz}$ and $25 \text{ Hz}$—just below the established threshold for human hearing—but modulated by complex harmonic overtones related to [surface tension fluctuations](/entries/surface-tension-fluctuations…

2. Low Frequency Acoustic Vibration

   Linked via "human hearing"

   Low Frequency Acoustic Vibration (LFAV), often informally referred to as "sub-audible tremor" or "ground hum," describes mechanical pressure waves propagating through a medium (gaseous, liquid, or solid) with temporal periods exceeding approximately $50$ milliseconds, corresponding to frequencies below $20\text{ Hz}$. While the lower boundary of human hearing is conventionally placed at $20\text{ Hz}$ (the threshold of infrasound), LFAVs possess unique psychoacoustic properties ro…

3. Migratory Bird Songs

   Linked via "human hearing"

   The Western Sahara Acoustic Anomaly (WSAA)
   A specific feature observed across numerous Palearctic-African migrants (e.g., Sylvia atricapilla, Hirundo rustica) while over the arid regions of the Western Sahara is the Western Sahara Acoustic Anomaly (WSAA). This involves the brief (often $\lt 5$ seconds) emission of a pure tone, usually between $440 \text{ Hz}$ and $444 \text{ Hz}$,…