Heavy Hammers / High Ratio / Ric

[Richard Brekne]

Delwin D Fandrich wrote:

> ----- Original Message -----
> From: "David Love" <davidlovepianos@earthlink.net>
> To: "Pianotech" <pianotech@ptg.org>
> Sent: September 24, 2003 11:46 PM
> Subject: Re: Heavy Hammers / High Ratio / Ric
>
> > Even if saturation were not an issue, it seems that  the upper level that
> > the piano will produce is limited by the soundboard.
>
> Actually, no. The upper power level any given piano is limited by the
> hammer velocity X hammer mass equation. And that is limited by action
> saturation. If you can increase hammer velocity with a given mass, or
> increase the hammer mass without sacrificing velocity, most, if not all,
> pianos are capable of producing more volume.
>

This has been my experience as well, tho I suppose at some point you could
perhaps overdrive the <<speaker system>> as it were. Whether it is possible to
produce an action that will do this is another matter. In any case, it is not
in my experience that hammers are capable of delivering enough power to the
strings to cause any such distortion. That the sound can get muddy at high
power playing more likely comes from hammers being much less precise at impact.
At least thats what I hear. Most times I can change to a tighter centerpin and
that alone will clean up sound at hard play quite a bit. Other things can be
done as well.

> Now I'm getting into an area I've not actually tested, but.... I think the
> distortion heard at this point is coming from a hammer gone out of control.
> As you approach action saturation the motion of the hammer becomes
> increasingly erratic -- it ends up flopping all over the place. This can
> easily be seen using high-speed photography to slow down the hammer's
> motion so it can be studied in slow motion.
>

This makes most sense to me. Most all distortion like noise IME comes from
either the hammers intonation being bad, or something causeing it to not hit
the strings squarely every time. It only stands to reason that the more  the
shank is contorted around, the more difficult its going to be to get a clean,
solid sound.


>
> >From my own tests with removing the compliance from various action
> components I do know that it is possible to increase sound volume without
> introducing any noticeable distortion if you can control the motion of the
> hammer more precisely.
>

So what is it about loud booming sound then that you find unattractive then Del
? Am I mistaken in understanding you much prefer to limit the upper volume
level of the piano ? Why ?


>
> One easy way to do this is to simply change the shape of the hammershank.
> The currently in vogue hexagonal hammershank cross-section shape is not the
> best. In fact, it's not really very good at all. Many early action makers
> used a rectangular shape well out toward the end of the shank. Some of the
> Pratt-Read shanks we used in the 1970s started out with this rectangular
> shape extending out about 3/4 of the length of the shank in the bass, about
> half way through the tenor, and about 1/4 the length in the treble. Why
> this is no longer done is a mystery to me. I guess the idea didn't
> originate in Germany.
>
> Del
>

Thanks for your thoughts Del.

RicB


--
Richard Brekne
RPT, N.P.T.F.
UiB, Bergen, Norway
mailto:rbrekne@broadpark.no
http://home.broadpark.no/~rbrekne/ricmain.html
http://www.hf.uib.no/grieg/personer/cv_RB.html