coupled motions

[Ron Nossaman]

At last, something technical. This is interesting. I've often wondered what
I was actually getting away with in tuning unisons. How far into the tone
did you tune? Were you giving it a second for the attack to coalesce, or
hitting the key quickly and continuously as you tuned? I'm thinking that
after the first half second or so of the attack, the note gets cleaner as
everything pulls together. I have found that attack distortion lessens as
the unison is better tuned, so I get better unison tuning in the attack,
than I do in the decay. Did you try it the other way and tune each
individual string as perfectly as possible with the RCT, muting the others,
and measure the pitch of the resulting unison?  

I'm also curious as to what factors determine how much tuning divergence
will pull together to an 'acceptable' level. String termination and the
impedance of the bridge/soundboard assembly would surely affect this, as
would the frequency, I would think. You probably have a tentative hypothesis
about what you've got so far, so what do you think?

Ron


>Hi,
>
>I decided to try an experiment.
>
>The tools:
>
>RCT for win95 using a pzm microphone , 40" Gerhard spinet equipped with
>humdity control and tuning stabilized to no note moved more than 2 cents on
>yearly tunings. 
>
>The note:
>
>F4 (it is good enough for Dr. S, so it should be a good choice), microphone
>resting with the mic facing the piano strings and the edge of the mic just
>being missed by the f4 key, music desk removed.
>
>RCT set with no calculated tuning (like a SAT with no stretch calculation
>or fac)
>
>The f4 was played 20 times then tuned aurally to the best of my ability.
>Readings are taken sequentially so as to minize drift due to heating or
>other factors.
>
>f4 at f4 all three wires.
>
>-2.50;-2.59;-2.38;-2.04;-1.49
>
>f4 at f4 bass wire
>
>-.94;-1.31;-1.76;-1.45;-1.05
>
>f4 at f4 middle wire
>
>-.84;-1.41;-1.25;-1.50;-1.22
>
>f4 at f4 treble wire
>
>-.99;-.70;-.73;-1.10;-1.48
>
>f4 at f5 all wires
>
>-.50;-.93;-.82;-.47;-.90
>
>f4 at f5 bass wire
>
>+.49;+.48'+.38;+.23;-.10
>
>f4 at f5 middle wire
>
>+.20;+.03;-.32;-.13;+.01;-.06
>
>f4 at f5 treble wire
>
>+.28;-.10;-.34;-.01;-.34
>
>f4 at c6
>all
>+4.52;4.51;4.45;4.80;4.44
>bass
>+4.44;+4.44;4.57;4.49;4.54
>middle
>+4.64;+4.69;4.63;4.68;4.76
>treble
>+4.73;+4.55;4.50;4.67;4.66
>
>f4 at f6
>all
>6.37;5.84;5.71;5.91;5.62
>bass
>6.15;5.94;5.95;5.43;5.44
>middle
>7.16;6.46;5.71;5.73;5.44
>treble
>6.17;5.51;5.54;5.87;5.68
>
>f4 at a6
>all
>-3.24;-3.03;-2.62;-3.19;-2.76
>bass
>-2.42;-2.39;-2.51;-2.59;-2.54
>middle
>-2.75;-2.40;-2.64;-2.71;-2.40
>treble
>-2.89;-2.57;-2.64;-3.10;-2.98
>
>f4 at c7
>all
>18.60;18.54;18.88;18.61;18.62
>bass
>18.89;19.11;18.11;18.91;18.95
>middle
>18.55;18.56;18.80;18.33;18.99
>treble
>18.86;18.74;18.74;19.07;18.86
>Regards,
>Don Rose, B.Mus., A.M.U.S., A.MUS., R.M.T., R.P.T.
>"Tuner for the Centre of the Arts"
>drose@dlcwest.com
>http://www.dlcwest.com/~drose/
>3004 Grant Rd.
>REGINA, SK
>S4S 5G7
>306-352-3620 or 1-888-29t-uner
>
>
 Ron