Overview of Partial Changes in ETD Tuning
Partial changes are an inherent aspect of using any Electronic Tuning Device (ETD) for tuning a piano. These changes occur because different partials are utilized for tuning various sections of the piano: the bass, midrange, and treble.
Selection of Partials in ETD Systems
Each ETD tuning system employs specific partials, and the selection of which partials to use is determined by the designer of the tuning system. As a result, different ETDs may apply different partials for the same piano section, leading to variation in tuning approaches. For instance, one system may use the 12th partial in the bass, another may use the 8th partial in the bass, and yet another may use the 3rd or 4th partial in the tenor. These choices reflect the preferences and decisions made by the programmer of the ETD tuning system. Consequently, partial changes can occur at various points, such as between G#2/A2, B2/C3, or D#3/E3, depending on the system.
Definition and Example of a Partial Change
A partial change in an ETD’s tuning occurs when the device switches from using one partial to another between adjacent notes. For example, consider a tuning system where the 6th partial is used for bass notes A0 through B2, the 4th partial for notes C3 through B4, and the fundamental (1st partial) for treble notes C5 through C8. In this scenario, partial changes happen at the boundaries between these sections:
- Between B2 and C3, the ETD shifts from the 6th partial to the 4th partial.
- Between B4 and C5, the ETD shifts from the 4th partial to the 1st partial.
Detecting Partial Changes in Tuning Settings
These transitions can be observed in the cents settings of the notes involved. For instance, when tuning B2, the ETD uses the 6th partial (F#5), while for C3, it switches to the 4th partial (C5). This shift results in a noticeable discontinuity, or ‘hiccup’ in the cents values between the two notes. The cents reading for B2 might be 1.3, whereas for C3 it could be -3.4. A similar change occurs between B4 and C5, where B4 is tuned using the 4th partial with a setting such as 12.0 cents, while C5 uses the 1st partial, possibly with a setting of 0.5 cents.
Implications and Opportunities for Error
Partial changes are present in every ETD tuning system. Each partial change introduces a potential opportunity for tuning errors. Generally, minimizing the number of partial changes is preferable, as more partial changes can increase the likelihood of errors at each transition. However, these changes can be checked and corrected within the system, and there is one specific system and ETD capable of identifying and correcting such potential errors.