What stretch will give the perfect tune? Where is the "sweet spot" for a piano? How many stretch points are needed and where should they be placed? Does the style need to be tailored to the piano, or can one style fit all, or nearly all, pianos? These questions have been discussed by Kent Swafford in a series of articles in the Piano Technicians Journal, beginning with the July 2017 issue.
Kent Swafford has created what he calls a Twenty-First Century Tuning Style based on the work of Bernhard Stopper (see Europiano 3//1988
). Swafford argues very convincingly that the stretch should not be limited by focusing on pure octaves (i.e. the traditional approach used by most tuners), but pure perfect 5ths, 12ths, 19ths or 26ths should be considered as well. The focus should not be on any one note or interval, but more on the unity of sound. Some have argued that a pure 12th style may be universal. Swafford seems to prefer the pure 12th, but has provided the other styles that might be more appropriate for pianos with low or high inharmonicity, or for those who find the pure 12th style too much.