MusicianCV · TROctave reduction
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Tuning and pitch systems
Octave reduction · 3:1 → 3:2 → 1320 Hz ÷ 2 = 660 Hz
Fix a reference frequency before comparing tunings. An octave doubles frequency. Convert a frequency ratio to cents with 1200 × log₂(ratio).
Example
Read the ratio alongside the worked calculation. · 3:1 → 3:2 / 1320 Hz ÷ 2 = 660 Hz
Read the ratio alongside the worked calculation.3:1 → 3:2 1320 Hz ÷ 2 = 660 Hz
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How does a frequency difference differ from a ratio?
Answer
Moving the same interval to another pitch preserves the ratio. The difference in hertz can change.Related topics
Reading small pitch differences in centsReferences
Frequency and Pitch of Sound
Subject-expert review pending.