piano/violin

[Delwin D Fandrich]

----- Original Message -----
From: "Farrell" <mfarrel2@tampabay.rr.com>
To: <pianotech@ptg.org>
Sent: June 10, 2001 6:09 AM
Subject: Re: piano/violin


> I think the word resonate, as applied to the piano string/soundboard
> interaction, lacks an adequately precise definition for our use.
>
> Consider the following definitions from Webster's:
>
> Resonance:
> A) "Reinforcement and prolongation of a sound by reflection or by
vibration
> of other bodies."
> B) " in physics, the reinforced vibration of a body exposed to the
vibration
> at about the same frequency, of another body."
>
> Resonant: "Increasing the intensity of sounds by sympathetic vibration;
as,
> resonant walls."
>
> It seems to me there are two distinct ways to view the property of
resonance
> with respect to the piano string/soundboard interaction: 1) the soundboard
> can be said to resonate directly by the string vibration (via physical
> movement of the bridge), and that in turn makes the board resonate (or
> vibrate - same thing here) (definition A for "resonance" would work here);
> or 2) an area of the soundboard resonating via sympathetic vibration from
> the sound originating in another area of the soundboard (via transfer of
> energy by soundwaves through air).
>
> I have thought that resonance is restricted to a situation where an object
> is set into vibrational motion via AIR movement. So, in this case, #1 is
> false in that we are not talking about the board resonating, but rather
> vibrating via transfer of energy from the string to the board via the
> bridge. #2 would be true - given my definition, this is resonance -
> something presumably undesirable in a piano soundboard.
>
> Consider David's statement:
>
> > Of course it should resonate! (vibrate sympathetically with the source
> > of sound, i.e. the vibrating string.  How else does it transfer its
vibrations to the
> >air?  The word resonate (precise definitions of electrical & physical
resonance
> >notwithstanding)  means 'to resound, to vibrate sympathetically with some
source > >of sound', which string instrument tops
>
> I think he is using the term resonate to describe the transfer of
> vibrational energy from the string to the soundboard via the bridge
> (inconsistent with my understanding of proper use of the term "resonate").
> He uses the term "sympathetically". Is this meant to say that the board
> resonates at the same frequency as the string (via the bridge), or is it
> meant to say that the string vibrates, moves air, and the board is set
into
> motion via the moving air? He MAY simply be saying here that the
soundboard
> resonates with the strings (via the bridge). In this case, my
understanding
> of proper/accepted use of the term is inconsistent with David's - the
board
> is not resonating with the strings, but rather it is vibrating as a direct
> transfer of energy from the strings to the board via the bridge.
>
> My understanding of Del's statement:
>
> > Second, piano soundboards should not resonate.
> > They do, of course, but it would be best if they did
> > not. And, while I don't
> > know anything about violin design I rather suspect
> > that violin soundboards
> > shouldn't resonate either.
>
> (and please correct me if I am off base Del) - is that the soundboard
> vibrating as a direct transfer of energy from the strings to the board via
> the bridge is not resonance (perhaps we should use a term such as "primary
> soundboard vibration" for this?). He uses the term "resonate/resonance" to
> mean sympathetic vibration of an area of the soundboard due to vibration
of
> another area of the soundboard (i.e., a primary vibration of the
soundboard
> occurs via transfer of energy from the strings, which causes the transfer
of
> sound through the air, which in turn causes a sympathetic vibration of
> another area of the soundboard - and hence, the undesirable occurrence of
a
> soundboard resonating).
>
> Sorry if this was just too much verbiage to draw a distinction between two
> definitions of a term. I just thought it important to clearly understand
> that there is a difference (I sure hope I am like not totally wrong on all
> this).

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Nicely put, actually. In extreme cases--and there are more of these than
we'd like--you can feed a signal from a signal generator via a shaker into a
soundboard and easily pick out the problematic resonances. And, sure enough,
when you locate the notes corresponding to those frequencies, you have a
voicing problem.

-- ddf