[pianotech] YC Capo Bars

[Delwin D Fandrich]

Roger,

What you describe is an indicator of hardness at the point of impact, not
them material's ability to transfer energy. You can achieve the same effect
by alternately striking a surface with a hard hammer and then a soft hammer.
The vibration spectra resulting from the impact of the hard hammer will
contain more high frequency energy than will the impact from the soft
hammer. But the induced waveform of each will reach the other side (end) of
the pinblock sample in the same amount of time. (Well, almost the same
time--the speed of sound through wood varies slightly with frequency; it
decreases slightly with increases in frequency.)

A more appropriate test, I think, would be to measure the length of time it
takes for the induced wave energy to go from one end of the pinblock sample
to the other when the sample is alternately struck along the edge of the
glue lines and then on the flat lamina. (I'm assuming the glue lines would
be those immediately adjacent to the point at which the flat lamina is
struck.)

ddf

Delwin D Fandrich
Piano Design & Fabrication
620 South Tower Avenue
Centralia, Washington 98531 USA
del at fandrichpiano.com
ddfandrich at gmail.com
Phone  360.736.7563


-----Original Message-----
From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf
Of Roger Gable
Sent: Tuesday, September 21, 2010 11:14 AM
To: pianotech at ptg.org
Subject: Re: [pianotech] YC Capo Bars

Take a piece of pinblock stock about 12" in length, cut absolutely square in
the other directions and then hit it with a hammer along the edge of the
glue lines and then on the flat laminate. There is a difference is pitch.
The laminate side produces a lower tone with the edge glued side a higher
tone.
Roger Gable