Matched Helmholtz resonator sets enabled early Fourier analysis of sound

Evidence

Helmholtz resonators were made in matched sets to facilitate analysis of sound, each resonator exquisitely sensitive to only one particular frequency. A tuned and calibrated set of such resonators may be used to perform a Fourier decomposition of sound, at least to the degree of precision possible with a human observer. Resonators were essential tools of the Parisian instrument maker Rudolph Koenig and of Hermann von Helmholtz, who listened through them, with the open neck exposed to some sound and a small opening or nipple inserted into the ear canal, to check for the presence of a partial at the resonance frequency. Since the sound is so much louder inside the resonator, a little of it may be bled off into the nipple, making the sound at that frequency much louder at the eardrum than it would have been without the resonator. At first, Helmholtz used crude bottles, then glass resonators, of the shape in figure 13.3. Later, Koenig developed beautiful sets of calibrated brass resonators stamped with his famous monogram, some of which still exist in museums and are prized possessions of physics and psychology departments. Helmholtz called the resonators “crutches” because he felt a refined ear should be able to “hear out” the partials without them. Nonetheless, even with his refined ear, he needed them in many circumstances. — Eric J. Heller, Why You Hear What You Hear- An…, 1200

Categorization

• XREF: Directly relevant to ‘why we hear what we hear’: ear performs spectral analysis, and these resonators were the physical embodiment of that analysis. — connects to: Complex real-world sounds can be analyzed via Fourier analysis — David Howard, Jamie Angus, coustics and Psychoacoustics, 436; Blowing across a bottle mouth produces a Helmholtz resonance; Helmholtz resonators serve as transducers, amplifiers, and sound controllers. (+1 more)
• SHARE: Send to anyone into the history of acoustics or instrument making — Koenig’s monogrammed brass resonator sets surviving in physics departments is a delightful detail.
• SEED: Article angle: how Helmholtz’s ‘crutches’ — mechanical Fourier analyzers — prefigured the cochlea’s spectral analysis by decades.
• corroborated: 2 independent passages support this claim — Eric J. Heller, Why You Hear What You Hear- An…, 1200

Broader Connections

• Complex real-world sounds can be analyzed via Fourier analysis #expands (0.85) — David Howard, Jamie Angus, coustics and Psychoacoustics, 436
• Blowing across a bottle mouth produces a Helmholtz resonance #expands (0.75)