pinz

[Delwin D Fandrich]

----- Original Message -----
From: <A440A@AOL.COM>
To: <pianotech@ptg.org>
Sent: April 20, 2000 8:41 AM
Subject: Re: pinz


> As the angle of approach lessens, there is more bridge to cover, so yes,
it
> would require extensive notching to keep the same footprint.
>       There may be impedance questions, since wider string contact  may
favor
> more efficient trasmission of the lower frequencies, or large contact
areas
> may suppress the higher ones.  If so,   increased contact with longer
strings
> and lower notes would be desirable.  I bet Del F.  could post some pretty
> pertinent thoughts on this topic......?????
> Regards,
> Ed

----------------------------------------------------------

It's mostly a matter of providing adequate speaking length termination along
with the physical constraints of the material used in the bridge.

In the treble sections, most so-called 'modern' pianos use more-or-less
parallel stringing.  This places the various unisons quite close together.
This means that the bridge pins also must be kept close together.  There is
an obvious limit, of course, set by the diameter of the wire used.  In the
treble this is quite small so the pins can be spaced fairly close and can be
of fairly small diameter.  Indeed, they must be, because there isn't much
room.  Further down the scale, as the strings begin to flare and there is a
bit more room, the pins can be made some larger and spread apart a bit.

As for offset, this is determined by the minimum amount of string deflection
angle desired.  Typically, this should be about 10º.  Much less than this
and speaking termination becomes a problem and much more than this and
bridge longevity becomes a concern.

I've not found that particularly wide or narrow contact has much to do with
soundboard impedance or with energy transfer from string to bridge.  I could
be wrong, though.  I've also not done any testing to determine this one way
or the other.

Del