Harmonics above the seventh exceed auditory filter bandwidth and cease to be resolved

Evidence

In the spectrogram of the fourth sound, where all harmonics are present up to the twentieth, the lowest six or seven harmonics appear as horizontal bands of energy and are therefore resolved, but the energy in the frequency region above the seventh harmonic is plotted as vertical lines, known as “striations,” which occur once per cycle (recall the discussion about the temporal theory of pitch perception). This is because all filters with center frequencies above the seventh harmonic have bandwidths that are greater Figure 5. — David Howard, Jamie Angus, coustics and Psychoacoustics, 1528

Categorization

• DEFINE: Defines ‘striations’ — the vertical spectrogram pattern marking the transition from spectral resolution to temporal coding.
• XREF: Connects to the temporal theory of pitch perception covered earlier in this book. — connects to: A filter resolves a harmonic it is centered on even when bandwidth exceeds spacing — David Howard, Jamie Angus, coustics and Psychoacoustics, 884; Auditory filter bandwidth determines which harmonics of a note get resolved — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 879; Only harmonics separated by more than the ear’s critical bandwidth are resolved (+3 more)

Broader Connections

• Harmonics resolve only while their spacing exceeds the ear’s ERB #corroborates (0.98)
• Only harmonics separated by more than the ear’s critical bandwidth are resolved #corroborates (0.95)
• Only harmonics below the fifth to seventh are resolved individually by hearing #corroborates (0.95)
• Auditory filter bandwidth determines which harmonics of a note get resolved #corroborates (0.92) — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 879
• Unresolved harmonics smear together as frequency rises #expands (0.75)