Pianotech

  • 1.  Scale Ripper

    Registered Piano Technician
    Posted 04-05-2021 22:14
    I'm entering data into Scale Ripper. The unwound portion at the end of bass strings is one of the data points.

    Since unwound distance is usually different at both ends of the string, I'm using the average distance of the two. Is that correct? My logic is that inharmonicity is not dependent on location mass location.

    John Parham


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    John Parham, RPT
    Hickory, NC
    828-244-2487
    john440@me.com
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  • 2.  RE: Scale Ripper

    Posted 04-06-2021 09:53
    Have any knowledgable colleagues used Scale Ripper to analyze and design piano string scales?
    I believe this program was designed in collaboration with Darryl Fandrich.
    It requires a Windows operating system, does not work on Macs.
    Download is free.
    <https://github.com/natefoss/scaleripper>

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    Ed Sutton
    ed440@me.com
    (980) 254-7413
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    Original Message


  • 3.  RE: Scale Ripper

    Posted 04-06-2021 15:59
    I'm not so sure that Fandrich worked on scale ripper. John Rhodes would know for sure. When Darrell did send me scales to study, it was always on his own excel spreadsheet that included certain formulas he was working with at the time.

    -chris

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    Chernobieff Piano Restorations
    "Where Tone is Key"
    chernobieffpiano.com
    grandpianoman@protonmail.com
    Lenoir City, TN
    865-986-7720
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    Original Message


  • 4.  RE: Scale Ripper

    Registered Piano Technician
    Posted 04-10-2021 14:12
    Chris,

    Thanks for your response. I reached out to John Rhodes.

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    John Parham, RPT
    Hickory, NC
    828-244-2487
    john440@me.com
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    Original Message


  • 5.  RE: Scale Ripper

    Registered Piano Technician
    Posted 04-10-2021 16:14
    John Rhodes has provided very useful information about Scale Ripper data input. With his permission, here is his email for the benefit of all.

    Yes, the UW (unwound) column should contain the mean unwound (sum of both unwound ends divided by two) portion of the speaking length. This is consistent with Dave Roberts' usage.

    Try playing with that number on one of the wound strings to see the effect on the various graphs.

    Darrell had an interesting anecdote:  A grand he encountered in the field had a "wonky" bichord note with partials which would not align. Darrell used Cybertuner's Pianalyzer to separately characterize the partial tree of the two wound strings.

    He then modified the wrapped length of the string with lower inharmonicity by removing wrap turns. He said he carefully nicked the wrap with dike cutters and then unwrapped several turns to the nick, then broke the wrap wire off. I don't recall if he lowered tension first (!) He said it took only two tries removing a total of ~6 turns to get good alignment of the partials and a resulting clean unison.







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    John Parham, RPT
    Hickory, NC
    828-244-2487
    john440@me.com
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    Original Message