Rescaling for older soundboards

Erwinspiano@aol.com Erwinspiano@aol.com
Mon, 15 Nov 2004 00:26:22 EST


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=20
Joe,David
 Actually you're possibly both a bit right & wrong.  Wood that ages gets=20
harder & that could equate to some increase in stiffness  without an increas=
e in=20
mass. The tone perhaps changes  because of it but most likely its just a los=
s=20
due to a change  in impedance.
   I bought some air dried Sitka a few years back.  It had air dried 20 year=
s=20
in a barn in the heat & cold of the central valley  Ca. It was rough cut for=
=20
an eventual sailboat mast that never got  made.
 I had it resawed at a local mill that  does a huge amount of custom work &=20
the head guys comment was" that was some  hard wood". He couldn't believe it=
=20
was spruce. He said there were sparks flying  off the band saw blade & state=
d=20
that the nature of wood is to get  harder the longer it's dried. So take it=20=
for=20
what it's worth.
  Dale Erwin

I think that=E2=80=99s  backwards.  As boards get older  they get stiffness=20
challenged.  More loudness comes from being less  stiff, lower impedance, mo=
re energy=20
is absorbed by the board rather than  reflected back, so louder and less=20
sustain.  That=E2=80=99s why the epoxy method works as it  does.  It adds st=
iffness without =20
adding much mass.  Anyway, I sent  the post on the spur of the moment withou=
t=20
thinking it through.  People, of course, do compensate for  the change in=20
stiffness, meaning inability to support the string load, by  easing up on th=
e=20
bearing=E2=80=94as Ron N. pointed out.  It was just a thought.  Epoxy and ea=
se up on the=20
bearing,  rescale to correct and smooth out the scale is probably the better=
=20
way to  go.  =20
=20
David  Love
davidlovepianos@comcast.net =20





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