Polyphonic Tuning
Overview
This view shows the detune amount for up to five pitch classes. The data is displayed as a constellation of pitch and detune LEDs arranged in a circle. The detune amount is measured with respect to the tuning reference (as seen in the view centre). This view makes it easy to spot tuning issues.
Pitch LEDs
Each pitch LED represents a pitch class in the audio spectrum as follows:
- A label identifies the pitch class.
- Colour represents the pitch class.
Detune LEDs
Each detune LED represents the tuning status of a pitch class as follows:
- Radial position represents the detune amount (up to 50 cents) and direction (i.e. flat or sharp).
- Colour represents the pitch class.
Pitch Selection
Pitch selection is automatic and is limited to prominent pitch classes. The top position of the view is reserved for the most prominent pitch class.
Changing the Tuning Reference
To select a pitch class as the new tuning reference, tap anywhere in its corresponding sector area. The A4 tuning reference is then automatically adjusted by the detune amount of the selected pitch class.
Example: Complex Tone in Spectral Mode
The sound source is a complex tone with 10 harmonics and a fundamental frequency of 220Hz (A3). The harmonics fall into five pitch classes. Only four are displayed in this case because the fifth is too weak.
The detune LED constellation suggests that the A pitch class is in tune, while the others are not. In general, the pitch of individual harmonics (other than the fundamental and its octave variants) do not match the note frequencies used in the modern tuning system (i.e. 12-tone equal temperament). Due to the tuning ambiguity introduced by harmonics, the Spectral mode is not well suited for analyzing a polyphonic sound source. To reproduce this example, set the Audio Source to Complex Tone, and set the Analysis Mode to Spectral. |
Example: Complex Tone in Perceptual Mode
The sound source is a complex tone with 10 harmonics and a fundamental frequency of 220Hz (A3). The harmonics resolve to a single pitch class (ideal case).
The detune LED constellation shows that the A pitch class is in tune, as expected. To reproduce this example, set the Audio Source to Complex Tone, and set the Analysis Mode to Perceptual. |