Geoff's question about string tension brings to mind a question that has been unclear to me since day one. How do we define high tension scales verses low tension scales etc.? In the past, the answer given to me has been defined by the amount of string tension (in pounds) on a particular unison. I've always defined (in my head) high tension/low tension scales by the tension relative to the breaking point of a string. Why? The percentage of breaking point defines the "harmonic key" of that string, hence the overall tone quality of the piano. I've heard of string tension as low as 45% to a high of 67% throughout any given scale. Would not the average % throughout any given piano define that piano as high, medium, or low? Can anybody clarify this?