CAUT

  • 1.  adaptive float - again

    Posted 12-31-2024 15:32

    This concepts has been brought up a few times in the past. I'm noticing way more RH variability at the U in the last few years and this seems to be accelerating in the last year. From freezing to balmy and rainy from week to week... I'm sure many of you have experienced similar swings. 

    I think most of us can get a pretty decent one-pass tuning back to whatever pitch we select, but I've floated pitch for years to limit the cranking up and down;  the 'adapted' part would be to create a compromised tuning with the goal of giving the parts of the piano with the widest swings a little more room to move through the shifts in RH. I'm currently using PiaTune, which gives me a nice graph of starting pitches that is used for the overpull calculation. It can even show dots for the starting pitch of the last tuning which gave me the idea by seeing how the starting pitches 'breathe' through the changes. I may be able to show an image if I can figure out things here. 

    I find that I can compromise up to around 4 cents between octaves, which seems to be what others were recommending in the past - set the float for the bass strings, then above the break set the pitch above or below 1 Hz depending on which part of the seasonal swing, return to overpull pitch and repeat as needed above the strut (like yamaha U1) 

    Since I get a visual with PiaTune, and then can also smooth the actual measurements into a trend line, I've been experimenting with using that trend line to set the tuning (mostly in secondary practice rooms), limiting the excursion to around 4-5 cents. That way instead of a staggered float, I get a trended float which ends up playing pretty well and would hopefully translate into a better shift as the humidity ranges up and down. The goal would be a 'speed tuning' only at the extremes of humidity - close to the midrange, they get a decent tuning at 440. I'm just trying to come up with a method that doesn't add any time to what I already do.

    I know it is a pretty minor effect, but any little bit may be helpful... Anyone else find this type of compromise helpful over time?

    Happy New Year - time to run and get ready for next term!

    Ron Koval



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    Ron Koval
    CHICAGO IL
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  • 2.  RE: adaptive float - again

    Posted 12-31-2024 23:26
    Starting pitches for Kawai GS40 at 50% vs 35%

    This piano has a longer slope than most above the bass break - Kawai GS40 in a church - horizontal line would represent tuned to calculation, grey zone represents +/-10 cents. See the mirror effect - Red dots before tuning at 50%RH vs grey dots 35% RH. So floating the pitch from 438 to 442, but looking to keep the extremes from being so large in the future...
    Ron Koval



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    Ron Koval
    CHICAGO IL
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  • 3.  RE: adaptive float - again

    Registered Piano Technician
    Posted 01-01-2025 12:30
    Just a note on increased variability at universities: During the pandemic, public buildings upped the air exchange speed. I noticed the louder fan/wind noise, especially in the recital hall. Since the air is moving more, moisture exchange between air and wood is accelerated. I suspect this will continue to be the new normal (the old normal was bad enough to contend with).

    Regards,
    http://fredsturm.net
    www.artoftuning.com
    "Education is not preparation for life; education is life itself." John Dewey




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  • 4.  RE: adaptive float - again

    Posted 01-05-2025 13:28

    Yes, I've noticed the louder air movement as well. 

    The "copy the slope" experiment may be something to look at again in the future if it could be automated, but isn't worth the time for now. Instead, I've adopted a "step" approach, similar to what has been proposed before. I've been trying 4-5 cent steps - so far, only two steps from my overall float setting. That means right above the break for about an octave, I will alter by 8-10 cents, which means that above and below I'll need to alter by 4-5 cents to make sure no octave is more compromised. So far, the double octaves haven't been a problem...

    1. Set overpull to overall float level. Tune with overpull the full octave below break - 4 cents. Starting above the break, set overpull -8 cents, quickly checking octaves. Shift to overpull -4 again in the appropriate area. Repeat if needed above treble break.
    2. For rough and dirty, just tune the highest bass strings octave, and a couple of octaves up to get the step effect, then clean up unisons for a 15-20 minute "make it better" pass.

    Ron Koval



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    Ron Koval
    CHICAGO IL
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