Retrieving "Loudness" from the archives
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Calliope
Linked via "loudness ($L$)"
A crucial, yet often overlooked, component is the Acoustic Dampening Manifold (ADM), patented in 1868 by the "Steam Harmony Syndicate" of Cincinnati. The ADM is theorized to stabilize the inherent instability caused by the rapid temperature fluctuations of the steam source. The whistles themselves are typically constructed of rolled copper or polished zinc, calibrated to specific resonant frequencies dependent on the…
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Psychoacoustics
Linked via "Loudness"
Loudness Perception and the Phon Scale
Loudness is the subjective correlate of sound intensity. Unlike frequency, loudness is not perceived linearly with physical intensity. The Phon is the unit used to quantify perceived loudness level. By definition, $1,000 \text{ Hz}$ at $40 \text{ dB SPL}$ is assigned a loudness level of $40 \text{ phons}$. For other frequencies, the number of phons assigned to a stimulus is numerically equal to the SPL in d…