There have been some interesting posts on this subject recently, and what Fred Sturm describes does not surprise me at all. The bridge has mass, resonance, and resistance as well as some compliance, and that makes for a complex picture when it comes to mutual coupling. Fred is correct that aurally tuning all three strings of a unison to within 0.1 cent of each other is nearly impossible because they will frequency lock together before you get them that close. When aurally tuning unisons, better results can be obtained by individually tuning each side string to the center string than by tuning one side string to the center string and then the other side string to the two tuned strings. Someone also alluded to this: Merely shoving a mute in and pulling it out can warm a treble string enough to make it go 0.1 cent flat if one is too forceful about it. Sincerely, Jim Ellis
This PTG archive page provided courtesy of Moy Piano Service, LLC