ETD question re: unisons

[Joe & Penny Goss]

John,
If this is true and it well might be, why does not the pitch drop more when
the third string is added.
Joe Goss
imatunr@primenet.com
http://www.primenet.com/~imatunr/

----- Original Message -----
From: "John Meulendijks" <jmjmeulendijks@planet.nl>
To: <pianotech@ptg.org>
Sent: Monday, February 19, 2001 3:22 PM
Subject: Re: ETD question re: unisons


> First I have to admit: I cannot keep up with all the messages. So maybe
this
> is already stated:
> One string brings in an amount of energy to the soundboard. The fixed end
is
> not a fixed end anymore. So the actual length of the string should be
> slightly enlarged to calculate the strings frequency out of it.
> Now three strings in unison bring their energy to the soundboard. I
presume
> this is more mass, more energy. The 'fixed' end on the bridge is even less
> fixed. If this is true, than the amplitude of the 'fixed'spot is bigger,
> thus the corresponding additional calculating length is bigger. Thus the
> resulting tone lower. Why should it occure in the upper middle and lower
> treble side? Because this is the spot where the central area of the
> soundboard is, and pressue........., and string tension........ etc.
>
> true?
>
> John Meulendijks
> Tilburg
> the Netherlands
>
> ----- Original Message -----
> From: Richard Moody <remoody@midstatesd.net>
> To: <pianotech@ptg.org>
> Sent: Monday, February 19, 2001 3:50 AM
> Subject: Re: ETD question re: unisons
>
>
> >
> >
> > ----- Original Message -----
> > From: Michael Jorgensen <Michael.Jorgensen@cmich.edu>
> > To: <pianotech@ptg.org>
> > Sent: Thursday, February 15, 2001 4:05 AM
> > Subject: Re: ETD question re: unisons
> >
> >
> > >  Many individual strings can full blush for several
> > > seconds (be very close), only to suddenly register flat-- a whole cent
> flat
> > for
> > > a brief instant and suddenly return to full blush.  Could the
soundboard
> be
> > > forcing/imposing a frequency against the will of the string and simply
> winning
> > > the battle for a second or less?
> > > -Mike Jorgensen
> > >
> > Of course the sound board is vibrating along with the string(s)  And the
> bridge
> > in between also.  But let us not forget that ETD's like all measuring
> machines
> > have limits.   At one point in our investigation we have to ask the
> question,
> > what are the limits, are we at the limit?.
> >     Another consideration that has not been addressed is that ETD's do
not
> > actually measure the vibration rate of strings themselves.  They give us
a
> read
> > out of what the microphone is picking up from sound vibrations excited
by
> a
> > soundboard excited by piano strings.  AND some are converting to
digital.
> It
> > would be interesting to see if magnetic or ceramic pickups gave the same
> or
> > different readings.
> >     This  gets to the determiniation of the accuracy of the instrument.
> If two
> > instruments (of different design) always give the same reading it is
> reasonable
> > to assume the readings are "true".  This begs the question, "how do the
3
> ETD's
> > (RCT, SAT, and TL (TuneLab) read a unison then a single string of that
> > ison?   ---ric
> >
>
>