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B2 tone on Kawai grands

  • 1.  B2 tone on Kawai grands

    Member
    Posted 09-19-2021 18:18
    Hi, all,
    Early this year I restrung my 50 year old Kawai KG-6C grand.  Good success overall.  I'm having a problem with the tone of the B2 trichord.  It has a "bong" sort of tone that I've tried to fix.  The problem is the strings are not level, and I haven't been able to raise the middle and right strings as high as the left string.  I was thinking the agraffe was funky and maybe needed to be replaced.

    BUT... a few weeks ago I tuned 2 other Kawai grands of different models, and they both also had the same problem.  The left B2 string was higher than the other two strings--enough that I could easily feel it with my finger.  They also had the unpleasant bonging tone.

    So now I'm wondering if this is an issue with the plate casting.  The B2 is right next to the strut, so I'm wondering if the point where the agraffe hole is is starting to slope up to the fillet of the strut thus slightly tilting the agraffe to the right.  It would explain the left string being higher.

    Any thoughts on my analysis and/or suggestions for remedying this problem?

    TIA,
    Eric

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    Eric Schell
    ericschellpiano@gmail.com
    Austin TX
    512-363-6236
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  • 2.  RE: B2 tone on Kawai grands

    Registered Piano Technician
    Posted 09-19-2021 19:10
    I have had some results by lowering a string. It’s basically the same process, but instead of lifting the right strings, you push down on the left string. Or, if you want to go to the trouble, remove the action and use a trunk hook to pull down on the string. You’re ding to same thing to the string.

    Wim.

    Sent from my iPhone




  • 3.  RE: B2 tone on Kawai grands

    Posted 09-20-2021 05:54
    Is this a 26-note bass section? How long is the piano? Plain wire throughout the low tenor? Hockey-stick long bridge, complete with shortened and low-tension low tenor?

    The height of the strings is simply a string leveling issue. If the above is true, regarding the bongy tone, are we not simply talking about the all-to-common poorly designed low tenor string scale? Did you evaluate the string scale? Did you rescale?

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    Terry Farrell
    Farrell Piano Service, Inc.
    Brandon, Florida
    terry@farrellpiano.com
    813-684-3505
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  • 4.  RE: B2 tone on Kawai grands

    Member
    Posted 09-19-2021 21:11
    Did you try seating the string at the bridge pins and at the hitch pin ? You might try taking some felt off the middle and right side of the hammer to get an even strike point if you can not get the left string to go down. Not sure if the bong is more  like a bell sound in which case the plate may be contributing to the sound. Also check hammer let-off. Perhaps it is too close to the point the hammer is almost blocking.

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    James Kelly
    Owner- Fur Elise Piano Service
    Pawleys Island SC
    843-325-4357
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  • 5.  RE: B2 tone on Kawai grands

    Member
    Posted 24 days ago
    Wim,
    I tried lowering the left string, but I have never had much luck doing that.  It's still high.
    Eric

    ------------------------------
    Eric Schell
    ericschellpiano@gmail.com
    Austin TX
    512-363-6236
    ------------------------------



  • 6.  RE: B2 tone on Kawai grands

    Member
    Posted 24 days ago
    James,
    It turns out that the bridge was the problem.  When I restrung the piano, there were a number of bent and one broken (!!!) bridge pins at the left end of the long bridge.  I replaced those and used CA glue on them.  When I revisited them yesterday they had again cracked the bridge cap a bit--the holes were enlarged a bit.  So I CA glued them again, and it was a vast improvement in the tone.  I'm happy with the result for now.

    Reshaping the hammer was the other idea I considered.  I'm "filing" that for later :)
    Thanks!
    Eric

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    Eric Schell
    ericschellpiano@gmail.com
    Austin TX
    512-363-6236
    ------------------------------



  • 7.  RE: B2 tone on Kawai grands

    Registered Piano Technician
    Posted 09-20-2021 09:43
    Eric,

    Please forgive me if this is a stupid question but...

    Did you follow the fact that the printed gauge numbers are metric, therefore smaller by about .001"?

    Pwg

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    Peter Grey
    Stratham NH
    603-686-2395
    pianodoctor57@gmail.com
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  • 8.  RE: B2 tone on Kawai grands

    Member
    Posted 24 days ago
    Terry,
    Yes it's a 26-note bass section.  The piano is 7'-4".  I guess you could describe the long bridge as a hockey stick although it's along continuous curve.  No, I didn't consider rescaling (that would be a new one for me).  I used the Kawai documented scaling combined with what was printed on the bridge.  I mostly opted for the smaller wire when there was a conflict.  I didn't want to add more tension to this 50 year old soundboard.
    Thanks for your response!
    Eric

    ------------------------------
    Eric Schell
    ericschellpiano@gmail.com
    Austin TX
    512-363-6236
    ------------------------------



  • 9.  RE: B2 tone on Kawai grands

    Member
    Posted 24 days ago
    Peter,
    Thanks for the tip re metric wire sizes.  That's a new one on me.  There was a number of 1/2 size discrepancies between what was printed on the bridge and the documented scaling I got from Kawai America.  That could relate to the metric/SAE difference in sizes (although the bridge numbers were typically smaller than the document).  I used the lower number whenever there a conflict trying not to add extra tension to the system.  Will keep this in mind when (or if) I restring a piano again.
    Thanks!
    Eric

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    Eric Schell
    ericschellpiano@gmail.com
    Austin TX
    512-363-6236
    ------------------------------