Damper Problems

jpiesik@arinc.com jpiesik@arinc.com
Tue, 14 May 1996 09:30:16 -0400


    Can anyone help me with a damper problem?

    The piano is a 1991 Schafer and Son 4'7" grand.  The first two bi-chord
    notes in the bass scale (C2 and C#2) continue to sustain after the
    dampers have settled onto the strings.

    The dampers are in perfect alignment in all dimensions.  There is plenty
    of damper follow.  There is nothing binding in the back action.  The
    damper wires move freely through the guide rail.  The felt wedges are
    rather wide at the point and settle very near the top of the bi-chord
    strings; however, they look similar to all the other bi-chord wedges.
    The sustaining sound is definitely coming from C2 and C#2 and is not a
    sympathetic vibration from somewhere else.  It seems like the dampers
    are coming down at a node on the strings because the sustaining sound
    appears to be a partial or harmonic of the fundamental.

    Do I need to needle the damper felt?  Is this a job for damper pliers?
    Do the dampers require some modification?  Would more weight on the
    underlever help?  Is this a design flaw the customer must live with?
    Any help is greatly appreciated!!

    John Piesik
    San Diego Chapter PTG
    JPIESIK@ARINC.COM




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