[CAUT] coupled motion and other myths

[Ed Sutton]

Keith-

The demonstration you cite may have been an example of both string coupling and para-inharmonicity.

At this time the most useful discussion of unison behavior in piano strings is probably Jim Ellis's series in September, October and November 1982 Piano Technicians Journal.  I recommend it highly.

Ed Sutton

  So Virgil played the checks that aurally, everyone in the room could hear the difference. Then Dr Sanderson tried to measure it and there was no difference. He changed the note he was reading, moving up the partial chain and low and behold the note was flatter at the the 4th partial. At least I think it was the 4th, may be the 3rd. Certainly some ETDs will not focus on the proper partial so the operater has to override. 

  The change in the partial structure will certainly make a tuner alter his tuning and I think that is the point Virgil was trying to make.

  Keith Roberts

   
  On 6/13/07, Richard Moody <remoody at midstatesd.net> wrote: 
    I am thinking about a research project hopefully resulting in an article, to get interaction from piano technicians about  such concepts as, "coupled motion"  "para inharmonicity", "longitudinal vibration" (did you really understand that article in PTJ?), "reverse well", "well temperament", and why the 3 string unison is flat from the first string tuned. I forget what they call that but I have a tuning machine that shows it isn't true. 
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