Pipe organ stops reinforcing non-octave, non-unison harmonics are called mutation stops

Evidence

Those stops that reinforce harmonics that are neither in unison (1:1) with nor a whole number of octaves away from (i.e., 2:1; 4:1; 8:1; … or 2n :1) the first harmonic are known as “mutation” stops. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1534

Categorization

• DEFINE: Names and defines the ‘mutation stop’ category by its harmonic relationship to the 8’ fundamental.
• XREF: connects to: A principal organ pipe’s first two harmonics dominate its spectrum — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1436; Pipe organ stops can reinforce non-octave harmonics to reshape timbre; Mutation stops reinforce harmonics not aligned with the octave series (+1 more)

Broader Connections

• Pipe organ stops can reinforce non-octave harmonics to reshape timbre #corroborates (1.00)
• Mutation stops reinforce harmonics not aligned with the octave series #corroborates (1.00)
• Pipe organs function as additive synthesizers by combining harmonics through stops. #corroborates (1.00) — David Howard, Jamie Angus, coustics and Psychoacoustics, 1551