Avery,
It seems to have become "on-list". Oh well.
Regards, Robin
Avery Todd wrote:
> Hey Robin,
>
> I'm glad this post was off-list! :-) Just kidding. Been there, done that!
>
> Avery
>
> At 11:57 AM 12/12/02 -0800, you wrote:
> >Hello Sarah,
> > I realized that I had misunderstood your description of the
> > situation with
> >your piano - I had been thinking that you were embarking upon a rebuilding of
> >it. If you will send back to me the numbers of the notes where the wires are
> >missing I can probably provide the correct wire size.
> > Another way to determine this is to look at the adjacent unison. If
> > there
> >is no single involved then they will come in sets of two - by this I mean
> >there
> >must always be the same wire on at least two unison due to the fact that the
> >looping takes one wire onto the bridge to serve as a string for the next
> >unison
> >and the other two in that unison must match it. Sometimes, it is possible
> >with
> >a little detective work to measure the adjacent unison and reach a
> >conclusion as
> >to the correct wire that is missing. However, if you will just send me the
> >number of the key, starting at 1 and counting up from the bottom, I will
> >likely
> >be able to find the size that was most likely used, at least, on a Steinway
> >grand.
> >Regards, Robin
> >
> >Sarah Fox wrote:
> >
> > > Hi Robin,
> > >
> > > I don't think we disagree. <smile>
> > >
> > > So you've rebuilt two Wissners?! How similar to mine? Were they 9'
> > > D-clones, by any chance? Circa 1933? I would love to know whether there
> > > are pins beneath those aliquots. It sounds as though there aren't. If you
> > > say they're not supposed to be tuned to sevenths (not ninths, actually),
> > > then the plates must have been moved.
> > >
> > > Also, do you know the original string diameters throughuot the tenor and
> > > treble? Avery Todd sent me some measurements on a Steinway D which
> > I'll use
> > > as a first-order approximation in the absence of any other data.
> > >
> > > Thanks for any info you can provide!
> > >
> > > Peace,
> > > Sarah
> > >
> > > ----- Original Message -----
> > > From: "Robin Hufford" <hufford1@airmail.net>
> > > To: "Pianotech" <pianotech@ptg.org>
> > > Sent: Thursday, November 21, 2002 2:59 AM
> > > Subject: Re: S&S D Duplex
> > >
> > > > Sarah, Gordon, and Dan
> > > > Yes, this is the sort of energy transmission I am trying to describe
> > > > here, although, the point I repeatedly make is that the transverse
> > > > behavior on the string is transduced mechanically by the terminations to
> > > > a forced, not free longitudinal wave and that means the frequency and
> > > > amplitudes are those of the forcing function. This is, in fact, what it
> > > > is, and that is the normal, ordinary, sound wave or mechanical wave
> > > > progation. They are, in essence, the same. A free longitudinal wave
> > > > is almost irrelevant to piano sound.
> > > > Additionally, through reflexion, constructive and destructive
> > > > superposition occur in the duplex as they do in the board thus creating
> > > > transverse behavior which, though resonance, becomes much greater in
> > > > amplitude than is the amplitude associated with a simple, free
> > > > longitudinal vibration.
> > > > I have rebuilt two Wissner's; they have the same duplex
> > > > arrangements as is found in Steinways, or at least, these did. I can
> > > > hardly believe, Sarah, that your piano should have a duplex tuning to
> > > > the ninth. Considering the incompentant restringing your have
> > > > described, this is most likely continuing careless on the part of the
> > > > restringer.
> > > > I have always been careful to tune the duplex on pianos I have
> > > > rebuilt, yet my experience is similar to Del's: I can't really tell a
> > > > significant difference. I consider myself to be neither a duplexephobe
> > > > nor a duplexephiliac as the duplexephone, in my experience, has been
> > > > somewhat duplicitous. (Thanks to Phil F for this little digression,
> > > > after reading his amusing description duplexaholic)
> > > > Regards, Robin Hufford .
> > > >
> > > > gordon stelter wrote:
> > > >
> > > > > And it seems to me that the more rigid a body, the
> > > > > more rapidly "shock wave" vibration would pass from
> > > > > one end to the other, as long as it was of uniform
> > > > > density to avoid internal damping. So if someone had a
> > > > > very stout steel rod, say 2" in diameter and 6 feet
> > > > > long, and tapped on one end, more vibration would pass
> > > > > through to the other end than on a rod which flexed,
> > > > > thereby dissipating the energy into the air, and
> > > > > losing it as heat in the internal flexion. And this
> > > > > longitudinal transmission would be virtually
> > > > > unnafected by bearing points, clamping, etc. Is this
> > > > > the sort of energy transmission we are speaking of
> > > > > here?
> > > > > Gordon Stelter
> > > > >
> > > > > --- Robin Hufford <hufford1@airmail.net> wrote:
> > > > > > A correction of one of the, unforntunately,
> > > > > > frequent typos in postings of late. rh
> > > > > >
> > > > > > There is a reasonable analogy to drawn between the
> > > > > > flexural, bodily,
> > > > > > behavior of the tines of the fork and the
> > > > > > transduction of this to a cyclic
> > > > > > vibration or stress wave passing through the(STEM
> > > > > > )(corrected version) and the
> > > > > > flexural, standing waves on the string which are
> > > > > > transduced similarly by the
> > > > > > terminations at the
> > > > > > bridge/board and agraffe/capo interface.
> > > > > >
> > > > > > Robin Hufford wrote:
> > > > > >
> > > > > > > Hello Sarah,
> > > > > > > The "pseudo-longitudinal wave" is, in fact, a
> > > > > > true longitudinal wave but it
> > > > > > > is a forced vibration and contains the
> > > > > > frequencies of the forcing function. It
> > > > > > > is the normal mechanical wave or density
> > > > > > fluctuation passing through a medium
> > > > > > > as the particles of the medium oscillate around
> > > > > > their equilibrium positions in
> > > > > > > the waveguide which, in this case, is mostly the
> > > > > > continuing portion of the
> > > > > > > string threaded across the bridge, the bridge
> > > > > > itself, the bridge pins, or the
> > > > > > > part of the wire passing through the agraffe,
> > > > > > along with the agraffe, Capo bar
> > > > > > > and plate. This is not a variation in tension
> > > > > > but, rather, again, a density
> > > > > > > fluctuation passing through the medium with a wave
> > > > > > velocity which is a function
> > > > > > > of the inertial and elastic properties of the
> > > > > > medium itself, imposed upon this
> > > > > > > is the frequency and extent or lack of
> > > > > > periodicity.
> > > > > > > This can be viewed in another way and that is
> > > > > > as a state of cyclic stress
> > > > > > > passing through the medium.
> > > > > > > Not to be too repetitive on the list as this
> > > > > > has been thoroughly explored
> > > > > > > in the threads referred to earlier, although
> > > > > > vehemently disagreed with by others
> > > > > > > here on the list: this can be easily comprehend
> > > > > > by considering the behavior of
> > > > > > > a tuning fork. The tines oscillate back in forth
> > > > > > at a right angle with regard
> > > > > > > to the stem. Their flexural, oscillating, bodily
> > > > > > behavior is mechanically
> > > > > > > transduced to a cyclic stress, strain, or density
> > > > > > fluctuation, as you will,
> > > > > > > which is a forced vibration passing along the
> > > > > > bass and stem of the fork. When
> > > > > > > placed in contact with the bridge, and it matters
> > > > > > little where, this vibration
> > > > > > > then passes into the bridge and board where
> > > > > > reflexion, superposition and its
> > > > > > > attendant interference, both positive and negative
> > > > > > create distortional and
> > > > > > > dilational waves in the board itself; momentum is
> > > > > > then radiated away as acoustic
> > > > > > > radiation. Precisely the same thing happens with
> > > > > > the vibrating string itself:
> > > > > > > the standing waves are enabled by the,
> > > > > > essentially, rigid termination
> > > > > > > mechanisms which transduce the strain energy
> > > > > > associated with the standing wave
> > > > > > > behavior in the wire into forced longitudinal
> > > > > > vibrations at the terminations.
> > > > > > > There is a reasonable analogy to drawn
> > > > > > between the flexural, bodily,
> > > > > > > behavior of the tines of the fork and the
> > > > > > transduction of this to a cyclic
> > > > > > > vibration or stress wave passing through the tines
> > > > > > and the flexural, standing
> > > > > > > waves on the string which are transduced similarly
> > > > > > by the terminations at the
> > > > > > > bridge/board and agraffe/capo interface.
> > > > > > > The longitudinal wave energy, at the
> > > > > > frequency of the forcing function,
> > > > > > > passes into the bridge with out need of flexion,
> > > > > > although I have never argued
> > > > > > > that flexion is completely absent for several
> > > > > > reasons, and, crosses the bridge
> > > > > > > and continues along the duplex where again,
> > > > > > reflexion and superposition create
> > > > > > > audible, tunable vibration.
> > > > > > > I don't know whether these segments increase
> > > > > > sustain or not, although, I
> > > > > > > have no doubt that, in some cases, the difference
> > > > > > in total sound, as I said in
> > > > > > > the previous post, increases the perceptibility of
> > > > > > the note produced by the
> > > > > > > speaking length, possibly in a kind of
> > > > > > gestalt/figure interaction. This would
> > > > > > > be very difficult to pin down, accurately.
> > > > > > > This view, which is rather unpopular here,
> > > > > > requires a subtle distinction to
> > > > > > > be drawn between the flexural, bodily behavior of
> > > > > > the vibrating portion of some
> > > > > > > object or structure, and the nature of wave
> > > > > > motion, or, again, localized
> > > > > > > density fluctuations which pass through a medium
> > > > > > and do not require actual
> > > > > > > bodilty motion of the medium itself for their
> > > > > > propagation. These are just the
> > > > > > > normal, ordinary mechanical waves encountered
> > > > > > everywhere. The function of the
> > > > > > > soundboard and bridge stabilize the endpoints of
> > > > > > the string and allow the
> > > > > > > transduction through mode conversion of strain
> > > > > > energy of the standing waves
> > > > > > > which are of course, primary, but, in another
> > > > > > sense secondary phenomena.
> > > > > > > Regards, Robin Hufford
> > > > > > >
> > > > > > > Sarah Fox wrote:
> > > > > > >
> > > > > > > > My other attempted post, accidentally directed
> > > > > > to Robin Hufford in
> > > > > > > > private...
> > > > > > > >
> > > > > > > > ----- Original Message -----
> > > > > > > > From: "Sarah Fox" <sarah@gendernet.org>
> > > > > > > > To: "Robin Hufford" <hufford1@airmail.net>
> > > > > > > > Sent: Monday, November 18, 2002 3:35 AM
> > > > > > > > Subject: Re: S&S D Duplex
> > > > > > > >
> > > > > > > > > Hi Robin,
> > > > > > > > >
> > > > > > > > > OK, thanks for explaining the "longitudinal"
> > > > > > wave to me (i.e. which isn't
> > > > > > > > > really a longitudinal/compression wave at
> > > > > > all). Steinway's "longitudinal"
> > > > > > > > > wave, if I understand you, is little more than
> > > > > > the variation in tension of
> > > > > > > > > the wire as it vibrates, resulting in lateral
> > > > > > forces (in direction from
> > > > > > > > > tuning pin to hitch pin) across the bridge.
> > > > > > Correct? I would think there
> > > > > > > > > must also be some transverse (e.g. vertical)
> > > > > > vibration in order for
> > > > > > > > cyclical
> > > > > > > > > tensional variations to result in any sort of
> > > > > > string vibration. Really I
> > > > > > > > > view the pseudolongitudinal wave (as you
> > > > > > explain it) as yet another aspect
> > > > > > > > > of a transverse wave. Of course I'd need to
> > > > > > think about it... and my
> > > > > > > > brain
> > > > > > > > > doesn't work all to great at this time of
> > > > > > night. <yawn>
> > > > > > > > >
> > > > > > > > > I suppose I would still echo Del's concern:
> > > > > > Does a pseudo-longitudinal
> > > > > > > > wave
> > > > > > > > > travel to the duplex segment through the wire
> > > > > > or through the bridge? I
> > > > > > > > > would argue that unless the string slips
> > > > > > freely on the bridge pins, which
> > > > > > > > it
> > > > > > > > > clearly doesn't, that the bridge would have to
> > > > > > move in order for
> > > > > > > > vibrations
> > > > > > > > > to pass into the duplex segment. I don't
> > > > > > think there's anything magical
> > > > > > > > > about it. On either side of the bridge, we're
> > > > > > still talking about
> > > > > > > > > garden-variety transverse waves, which are
> > > > > > tunable in every sense to which
> > > > > > > > > we have grown accustomed.
> > > > > > > > >
> > > > > > > > > As I see it, the fundamental questions are
> > > > > > still:
> > > > > > > > >
> > > > > > > > > (1a) Does an unmuted duplex segment increase
> > > > > > sustain? (1b) Does the
> > > > > > > > tuning
> > > > > > > > > of an unmuted duplex segment affect sustain?
> > > > > > > > >
> > > > > > > > > (2a) Are the tonal effects of a duplex segment
> > > > > > desirable? (2b) How does
> > > > > > > > > this differ between tuned and untuned?
> > > > > > > > >
> > > > > > > > > The first question can be answered
> > > > > > quantitatively. The second is a
> > > > > > > > > subjective matter, not unlike the age-old
> > > > > > argument as to whether a large,
> > > > > > > > > echoing concert hall sounds better than an
> > > > > > "anechoic" chamber -- or vice
> > > > > > > > > versa -- or some compromise inbetween.
> > > > > > Different strokes for different
> > > > > > > > > folks.
> > > > > > > > >
> > > > > > > > > Anyway, thanks for explaining what is really
> > > > > > meant by this "longitudinal
> > > > > > > > > wave" thing. It makes much more sense now.
> > > > > > > > >
> > > > > >
> > > > > === message truncated ===
> > > > >
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