[pianotech] Drilled capo bars

[Nicholas Gravagne]

Hi Daniel,

On Thu, Mar 10, 2011 at 10:24 AM, Daniel Carlton
<carltonpiano at sbcglobal.net> wrote:
> Anyone care to say anything about drilled capo bars? Has anyone besides
> manufacturers tried this, and had success or not? How exactly is it supposed
> to contribute to “exceptionally long sustain?”

Could you please explain this. Where are these holes drilled? How
large, aprox.? Do you mean drilled from underneath in order to tap in
special agraffes or other hardware? What mfg. is doing this? Are these
capo bars unusually massive? And who is claiming "exceptionally long
sustain"? If the "who" in this is too sensitive for you to divulge,
what more can you tell us?

> By removing mass from the
> bar/giving the bar more freedom to vibrate? I'm not an engineer so help me
> out here, please.

While awaiting answers above, in general, allowing (or encouraging)
the capo bar freedom to vibrate is counter-physics for increasing
sustain. String energy will find a happy friend to dance with (the
capo being a real mover and shaker) and the two will complete the
dance sooner than later. Although plates, bar, struts and rims do
vibrate, by far most of the vibratory action going on should be
consolidated in the strings and soundboard assemblies.

If there exists any objective proof or data to the claims above may we
know of it? Should proof exist, then something very unusual is going
on. In any case, if the practice is working on the Battleship series
of grands doesn't mean it will transport well to rebuilding shops.
Still, I may have to get out my big momma, mega-torque drill.

-- 
Nick Gravagne, RPT
AST Mechanical Engineering