Pianotech

  • 1.  Pitch droop as the sound volume decreases

    Posted 08-02-2023 20:10

    Yesterday I had the privilege of being asked to tune 2 pianos that belonged to a private piano teacher.  The first piano I worked on was a Yamaha GA1.  As I was working on it I noticed that almost all of the notes, when played FFF would start out sharp and noticeably go flat as the volume of the note decayed.  If I remember correctly Randi Potter's material talked about this phenomena and explained is as due to the high volume sound stretching the string more and thus causing the note to be sharp.  Randi even taught tuning technique to consist of both a "tuning blow" and a "test blow".  Since I've been doing this now for a while (probably over 500 tunings under my belt) I've had a chance to observe this phenomena to a greater or lesser extent however this GA1 exhibited it more that I have ever experienced.  As I was working on the other piano (a Yamaha P22) not only did it not have nearly this behavior, but it also made me try to speculate as to why some pianos may have it worse than others.  The hypothesis I came up with was that perhaps it's because the strings are old (piano is probably at least 30 years old) or just a victim of a bad lot of string material.  Either way I'm wondering if I should recommend that the piano be restrung or if there is something else causing this that I should mention to the owner.

    Thanks in advance for the helpful comments that I am sure I will get.



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    Neil Vanderschaaf
    Round Rock TX
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  • 2.  RE: Pitch droop as the sound volume decreases

    Registered Piano Technician
    Posted 08-02-2023 20:29

    I got my initial chops from the Randi Potter course, too. Though, a long time ago. 

    First of all, you don't need to play FFF to tune. In fact, playing that hard can sometimes cause tuning instability problems. F is plenty sufficient for tuning, and a sharp, perhaps FF, is probably fine for test blows on most pianos. Your hands, and the piano, will thank you. DAMHIK.

    I hear the same thing as you describe in most pianos. Newer, brighter strings seem to exhibit it more than older dull strings. I've come to the personal conclusion that what I'm hearing is not the note going flat, it's the loudest higher frequency partials fading out one after the other, top to bottom. You'll hear the loudest higher frequency partial fade out which lets you then hear the next loudest highest frequency partial, which is, naturally, at a lower frequency. And so it continues until the note dies out entirely. And since partials are not all evenly dividable by two, as the partials, one after the other, highest to lowest, loudest to quietest, fade out one after the other it can give the effect of the note going down in pitch. It's not. I find it a very interesting phenomena. 



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    Geoff Sykes, RPT
    Los Angeles CA
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  • 3.  RE: Pitch droop as the sound volume decreases

    Posted 08-02-2023 21:47

    Geoff,

    Thank you for your comments.  Actually I got out my Accutuner IV and watched the pitch move from sharp to flat.  I'm pretty sure that it doesn't change which partial it "listens" to as the volume of the note decreases.  Also, I started playing FFF when I noticed the behavior, not necessarily during the actual tuning process.



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    Neil Vanderschaaf
    Round Rock TX
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  • 4.  RE: Pitch droop as the sound volume decreases

    Registered Piano Technician
    Posted 08-02-2023 22:01

    I believe FFF increases the tension on the string. What happens when one increases tension!



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    Larry Messerly, RPT
    Bringing Harmony to Homes
    www.lacrossepianotuning.com
    ljmesserly@gmail.com
    928-899-7292
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  • 5.  RE: Pitch droop as the sound volume decreases

    Registered Piano Technician
    Posted 08-02-2023 22:37

    I often feel like pianos are much like people. Some exhibit weird and bizarre behavior for no "apparent" reason. I have experienced the phenomenon you have described. Worst case was a Steinway L that was so weird in this way it was quite difficult to tune (I'm analog tuner...aural). Owner just plain didn't like the piano much. Eventually I restrung it and it was MUCH better...but after a few years the sane problem started to creep back in. I think it was in it's DNA. 

    He eventually replaced it with a B. No issues. 

    Peter Grey Piano Doctor 



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    Peter Grey
    Stratham NH
    (603) 686-2395
    pianodoctor57@gmail.com
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  • 6.  RE: Pitch droop as the sound volume decreases

    Registered Piano Technician
    Posted 08-03-2023 09:10

    "…I'm wondering if I should recommend that the piano be restrung or if there is something else causing this that I should mention to the owner."

    Has the customer mentioned anything? Customers don't notice many things technicians hear (or feel-many have no idea what aftertouch is). Another question is whether the customer even plays loud enough to cause the phenomenon. Maybe it's not really a problem?

    By the way, bowed string instruments exhibit this pitch change as well: dig into the string with the bow and the pitch will rise. It's subtle though, and the use of vibrato, including the width, tends to increase with volume. So it's not an issue, especially because it's transient.



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    Scott Cole, RPT
    rvpianotuner.com
    Talent, OR
    (541-601-9033
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  • 7.  RE: Pitch droop as the sound volume decreases

    Registered Piano Technician
    Posted 08-03-2023 10:01

    Electronics has a way of exhibiting things that were there all the time but our brains made an adjustment. Then we SEE it and all of a sudden it's a "problem". 

    Virgil Smith noted essentially the same thing decades ago and developed compensatory analog algorithm to deal with it. If it's pronounced, it simply creates more of a challenge in tuning, but in general I don't consider it a big problem (only if it fluctuates up and down repeatedly, which is what that L did, am I likely to bring it to anyone's attention). Simply an annoyance otherwise.

    Scott, yes I used to notice it in my cello playing (back in the day). 

    Peter Grey Piano Doctor 



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    Peter Grey
    Stratham NH
    (603) 686-2395
    pianodoctor57@gmail.com
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  • 8.  RE: Pitch droop as the sound volume decreases

    Member
    Posted 08-03-2023 22:26

    Do a search on Yamaha GA1. there are some recent posts about tuning stability, scaling issues as well as some suggestions. 



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    James Kelly
    Owner- Fur Elise Piano Service
    Pawleys Island SC
    (843) 325-4357
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  • 9.  RE: Pitch droop as the sound volume decreases

    Registered Piano Technician
    Posted 08-04-2023 01:48

    Neil,

    The Yamaha GA1 was a transition model from about 2001 to 2005 and was replaced by the GB1 which corrected some string scaling issues. The GA1 lowest 6 plain wire notes (27-32) are way under tensioned (90lbs per string up to 124 lbs per string) and I am wondering if the pitch drop was more pronounced in this area. Let me know if this is the case.

    As for restringing you might want to look at one of my web pages: http://www.goptools.com/bassretro/ where I converted the lowest 6 plain wire notes to bichord bass notes. This corrected the tension problems and also improved overall stability. There is also a white paper there that I wrote concerning the conversion.



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    Tremaine Parsons RPT
    Georgetown CA
    (530) 333-9299
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  • 10.  RE: Pitch droop as the sound volume decreases

    Posted 08-04-2023 21:24

    Once again I am grateful for the comments.

    There are several reasons I've had for posting this question.  My first and most important being that I was wondering if this behavior was a warning, a canary in the mineshaft so to speak, of something more serious to develop.  This doesn't seem to be the case.

    As far as my client goes, Scott, no she had never noticed it and won't worry about it unless I come back with some dire prediction of impending doom.

    The last reason is that, as a trained engineer, I find the puzzle as to why it is happening intriguing.  I have tried to create a list of some of the possibilities:

    1. The metallurgy of the strings used.
    2. The use of the AccuTuner to monitor the pitch variation.
    3. A reaction of the tuning pins, agraffs, capo bar, bridge or hitch pins to the wild excursions of the string.
    4. A change in the atmospheric composition such as a higher concentration of Helium when the note being played is loud.  OK, I'm not really taking this possibility seriously, but it does sound like it could be an interesting experiment to run.

    So one of the good things that came out of this is that I had never taken the time to map out which partials the AccuTuner listens to.  For the setup I was using, it turns out it doesn't start using the 1st partial (fundamental) until C6.  I can't remember if I was worrying about this in that range of the piano or not.  Something I'll keep in mind the next time I have a chance visit the piano.

    I also plan to go back and study in 

    Once again, thanks and if this has triggered any memories or experiences I'd love to hear about them further.



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    Neil Vanderschaaf
    Round Rock TX
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