Proximity resonance in gramophones is the same gatekeeper effect as trumpet mouthpieces

Evidence

We had a much earlier example of a gatekeeper resonance and many references to it since: proximity resonance, as in the Edison gramophone reproducer (see figure 7.6). In that case, because of very early in-phase reflections, the gatekeeper resonance induces a very broad resonance that begins at zero frequency and continues for much of the audio range. It “shapes” the power spectrum of a complete gramophone, just as a trumpet mouthpiece sculpts the spectrum of a trumpet into a peak around 800 Hz. — Eric J. Heller, Why You Hear What You Hear- An…, 1498

Categorization

• XREF: Unifies the earlier gramophone reproducer analysis (figure 7.6) with the current wind-instrument gatekeeper discussion — the same mechanism across wildly different instruments.