Curve on Bridge Bottom

[Delwin D Fandrich]

----- Original Message -----
From: "Farrell" <mfarrel2@tampabay.rr.com>
To: <pianotech@ptg.org>
Sent: May 02, 2002 5:17 AM
Subject: Re: Curve on Bridge Bottom


> Again, I think I am really asking two questions here: First, from a
practical standpoint - you have already said there doesn't seem to be much
difference - I'll take you at your word. Second, from a theoretical
standpoint - I should think there would be at least a theoretical advantage
(and if so, perhaps a small, barely perceptible practical advantage -
perhaps the practical advantage might only show up after thirty years, as
maintaining original crown better?).


Terry,

As Cy said, "In theory, practice and theory are the same, but in practice,
they are not...." Great quote, that! You can make a theoretical argument for
this being the case, but in practice there seems to be no difference. Well
regarded companies can be sited on both sides of the issue.

Personally, I've never been able to attribute any nuance of performance --
either good or bad -- to either camp. So we put them on flat.

I might suggest a small experiment: go ahead and carefully crown the bottom
of a real-world tenor bridge to match the curve of an installed soundboard.
Now, place this bridge on your workbench and see how much force it takes to
depress the middle of the bridge flat against the workbench top. Doesn't
take much, does it? That's how much 'assistance' the bridge is donating to
the formation and maintenance of your crown. A well designed set of crowned
ribs will do you a lot more good.

Del