Bill Maxim writes; >At the North Carolina Conference this past weekend, Dean Reyburn >was demonstrating the Cybertuner when the question was raised. We >experimented with it and after tuning a unison, single strings >consistently showed a few hundredths of a cent sharper than did the >unison with the mutes pulled out. > I was only able to do a short demo of this in the class because of time but I seem to remember RCT showed up a difference about the same as Jim's results did, about .5 or .6 cents or so. >It made me a believer, but I cannot use this information in any >practical way. So far as I am concerned, it is purely academic, >such a nit-picking detail that there is no need for me to try to >apply it to my tuning. > There is some practical application here. The difference between the single string and the unison is often several tenths of a cent, well within the ability of a good aural tuner. Jim Coleman Sr. has found that this phenomenon primarily shows up in the midrange, and is not as noticable in the treble or bass. If one mutes up the whole piano and tunes either aurally or to a visual tuning device (or both) and then unmutes and tunes unisions on 88 notes, it seems likely to me that some of the octaves will change stretch, especially those which have one note in the midrange and another outside. At the "Tune-Off in Chicago" Jim used Reyburn CyberTuner's "overpull" cents offset window to compensate for it. An aural tuner could compensate for this by stretching the octaves going down into the bass just slightly since the midrange will fall a bit after the unisons are tuned. The treble also might not need as much stretch as you would otherwise assume. Maybe some aural tuners already compensate for this automatcially from many years of practice? The other answer would be to tune the midrange, then tune the unisons perfect, THEN tune up and down from the unmuted midrange. I think that was one of Virgil's points in very fine concert tuning; check the piano with all unisons sounding. -Dean ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Dean L. Reyburn, RPT 2695 Indian Lakes Road Cedar Springs, Michigan, USA web page: www.reyburn.com 1-888-SOFT-440 (or 616-696-0500) email: dean@reyburn.com
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