Organ pipes’ timbre arises from resonances cooperating with edge tone

Evidence

One does not always want to maximize energy flow across junctions between two parts of a system. We need the impedance mismatch at the bell end of a trumpet or clarinet to cause reflections and define its resonance frequencies. Impedance mismatches are carefully controlled to achieve desirable timbre in wind and string instruments. For string instruments, large mismatches are required at the points between which strings are stretched, lest the vibrations drain away too rapidly, rendering the string frequencies ill-defined. The infamous wolf note of cellos is a breakdown of this requirement (see section 18.7)—a near impedance matching where none was wanted. — Eric J. Heller, Why You Hear What You Hear- An…, 83 (#expands, via linked claim)

Organs have a number of stops on each manual of various footages, most of which are flues. Some are voiced to be used alone as solo stops, usually at 8′ pitch, but the majority are voiced to blend together to allow variations in loudness and timbre to be achieved by acoustic harmonic synthesis by drawing different combinations of stops. The timbral changes are controlled by reinforcing the natural harmonics of the 8′ harmonic series on the manuals (16′ harmonic series for the pedals). — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1526 (#corroborates, via linked claim)

Categorization

• XREF: connects to: Flute tone arises from jet instability locked to tube resonances; Vocal tract resonances measurably shape wind instrument timbre; Pipe organ stops can reinforce non-octave harmonics to reshape timbre (+6 more)

Broader Connections

• Pipe organ stops can reinforce non-octave harmonics to reshape timbre #expands (0.85)
• Instrument design exploits impedance mismatches to create resonance and timbre #expands (0.80) — Eric J. Heller, Why You Hear What You Hear- An…, 83
• Organists shape timbre by selectively reinforcing harmonics of one series #corroborates (0.78) — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1526
• Nicking the pipe edges smooths onset and suppresses high-frequency components #complicates (0.78)
• The pipe organ is history’s first additive synthesizer for timbre #expands (0.75) — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1524
• Chiff-voiced open pipes briefly sound an octave high at onset #exemplifies (0.72)
• Open and stopped organ pipes audibly start on different overblown harmonics #complicates (0.72) — David Howard, Jamie Angus, coustics and Psychoacoustics, 1471