Combination tones fill in missing harmonics of a perceived fundamental

Evidence

When the two pure tone frequencies are both themselves adjacent har­ monics of some f0 (in Example 5.2 the tones are the 11th and 12th har­ monics of 100 Hz), then the difference tone is equal to f0 and the other combination tones form “missing” members of the harmonic series. When the two tones are not members of a harmonic series, the combination tones have no equivalent f0, but they will be equally spaced in frequency. — David Howard, Jamie Angus, coustics and Psychoacoustics, 1620

Categorization

• XREF: This ‘resynthesis of missing fundamental from combination tones’ evokes phenomena like the missing-fundamental illusion central to Chapter 5 and to ear-deception generally. — connects to: Nonlinear vibration generates new frequencies absent from the original stimulus; A combined waveform can produce a perceived pitch absent from its actual frequency components — Eric J. Heller, Why You Hear What You Hear- An…, 323; Listeners perceive the fundamental frequency even when its lowest partials are absent — Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 1115 (+5 more)
• corroborated: 2 independent passages support this claim — David Howard, Jamie Angus, coustics and Psychoacoustics, 1620

Broader Connections

• Combination tones exist below both source tones and vary in audibility #expands (0.85)