[CAUT] String Coupling / SB and Bridge stiffness...and maybe Pure Sound

[Richard Brekne]

Hi Ed...

I find myself in perfect agreement with your post, as I understand it. 
And Weinreich's article is often in the back of my mind as I ponder 
these issues.

Cheers
RicB


    Greetings,
             I am one of those, I think, but I allow it rather than
    produce it!   Since reading Gabriel. Weinreich's findings,

    http://www.speech.kth.se/music/5_lectures/weinreic/weinreic.html
    Gabriel Weinreich: The coupled motion of piano
     
    I began questioning exactly what I was looking for in a unison. 
    Then I bought a SAT and began looking at numbers.  The phase
    relationship can be altered by an unnoticeable difference in pitch
    to achieve the best sounding unsions, since it appears that the
    fullness and sustain of a unison doesn't necessarily depend on all
    three strings vibrating at exactly the same frequency.     Since I
    am in this for the money, I listen to customers.  One of my more
    seasoned performance customers, with many years of exoerience, told
    me that my tunings sounded better a day after I had tuned them. 
    This artist is a very forceful player and I had always tried to
    leave the piano as clean as possible.  I went back a day after a
    tuning to see what was the difference and could barely discern any,
    but there was the slightest drift in most of the unisons.  NOT a
    drift that caused a beat, since the sound died out before a full
    cycle could be heard, and not a drift that produced even a "yowl",  
    but the SAT would show that usually one of the three strings
    exhibited a tendency to be either sharp or flat from where I had
    left it.  I am talking about maybe a tenth or two of a cent. 
    However, this is enough to increase the sustain and apparent
    fullness of the note.

           The piano sound I get when all three strings stop the lights
    dead on is not the same as when I tune two strings to the lights and
    then place the third string by ear. I believe the latter approach is
    the way to go to get consistant unisons, since 'machine perfect'
    produces some notes that are crystal clear and some that are not. 
    By aurally tuning the third string, I think I am allowing a sensual
    judgement to determine the final sound, and the coupled motion is at
    the heart of this.  Some notes above C6 require an obvious variation
    to produce an acceptable unison.  And false beating strings often
    require even more divergence from exact to give the illusion of
    clarity.      I tune as cleanly as I can,  but the machine tells me
    that this often requires more than one pitch in a unison to achieve.
    I do this knowing that anything from soundboard movement to bridge
    expansion/contraction  will loosen up the unisons soon enough, and
    the durability of the tuning is better if I start the unisons "too
    clean", since from this starting point, it takes longer for the
    divergence to become apparent.  
     
    regards,  
    Ed Foote RPT