Sound waves(The behavior of soundboards)

[Carl Meyer]

Now my curiosity is aroused.  We now have three systems.

1.  An untaut string (perhaps cotton, braided dacron. or
     monofilament.

2.  A copper wire.

3.  A steel wire.

These three are happily transmitting sound from one place to another.

My question is.  "How does the inharmonicity compare in the   three
different experiments?"

Carl Meyer  Assoc. PTG
Santa Clara, California
cmpiano@attbi.com

----- Original Message -----
From: "John Delacour" <JD@Pianomaker.co.uk>
To: <pianotech@ptg.org>
Sent: Wednesday, January 23, 2002 6:00 AM
Subject: Re: Sound waves(The behavior of soundboards)


> At 6:40 PM -0600 1/22/02, Ron Nossaman wrote:
> >  >The string is not taut.
> >>
> >>JD
> >
> >It says that where?
>
> It says: "One end of a metallic wire is connected with the
> sound-board of a pianoforte, and the other taken through the
> partitions or floors into another part of the building"
>
> It is most unlikely that it was taut in these circumstances and
> certainly not necessary for it to be taut.  However it would have
> needed, I think, to be *fairly* straight.
>
> You can perform a similar experiment by drilling a 2mm hole in a
> grand piano bridge and planting a straightish length of 2mm copper
> wire, say 60 cm long, with one end ground flat firmly in the hole.
> Then take a tuning fork in one hand, hold the free end of the wire in
> the other and press the fork onto the ground end.  You will hear the
> sound amplified by the board.
>
> You can next hold the free end in a pair of small pliers and apply
> the tuning fork sideways to the pliers, or pointing in any direction,
> and get the same effect.
>
> If you next do the same with a *straightish* length of say No.16
> piano wire, the effect will be the same.  While the fork is still
> sounding and being amplified, you can then curve the wire into an arc
> and observe the effect as you curve it and straighten it.
>
> In neither case does the wire need to be taut, and if you were to go
> to the trouble of drilling right through the board and knotting the
> wire underneath so that you could apply tension to the wire, it would
> make very little, if any, difference.
>
> After all this, you can tell me how blindingly obvious it is that the
> fork moves the wire and the wire moves the bridge.
>
> JD
>