[CAUT] Action saturation

[Ed Sutton]

It is felt both ways, in combination. You play harder and harder, but it doesn't get any louder.
If it is ever felt as, say, a springiness while pressing slowly, I don't knows of this.
There are folks who have rebuilt a lot more pianos than I have, and they can give more information.
Ed S.
  ----- Original Message ----- 
  From: Laurence Libin 
  To: Ed Sutton ; caut at ptg.org 
  Sent: Wednesday, July 28, 2010 1:07 PM
  Subject: Re: [CAUT] Action saturation


  If the action rail flexes, can this movement be felt by the player's hands, or only sensed aurally?
  Laurence

    ----- Original Message ----- 
    From: Ed Sutton 
    To: caut at ptg.org 
    Sent: Wednesday, July 28, 2010 10:26 AM
    Subject: Re: [CAUT] Action saturation


    Incidentally, if there is a problem with the Steinway action rail flexing, it will probably be more obvious (weaker sound) in the middle of the rail section, with the least flexing at the section ends (stronger sound).
    es
      ----- Original Message ----- 
      From: A440A at aol.com 
      To: caut at ptg.org 
      Sent: Wednesday, July 28, 2010 8:53 AM
      Subject: [CAUT] Action saturation


      Ed Sutton writes: 


        Action saturation.
        As the pianist plays harder, the action parts flex more, so that eventually
        the force delivered to the string is determined by the whipping movement of
        the parts rather than the speed of the stroke to the key. The acceleration
        of the hammer has reached its peak. The pianist plays harder, but the only
        sound that gets louder is the thump to the keybed. 


      There is a great example of this in the "Five Lectures" series.  By comparing timing of the action components during varied levels of force, it becomes apparent that at some point, the key is hitting the punching well beore the hammer has finished its acceleration.  Taken to an extreme, it is possible to bottom the key out before the hammer moves much at all. Which means that the force hitting the string is limited to whatever compliance is found in the action.  I think the key is responsible for most of this, though the hammershank would run it a close second. The balance rail punching, capstan felt, and knuckle compression would come in third, with the small amount by rail flex and pin bushings contributing a little more.  
      Regards,. 
      Ed Foote RPT
      http://www.uk-piano.org/edfoote/index.html
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