Up & down vs; side to side string motion was; false beats from ?? -...

KeyKat88@aol.com KeyKat88@aol.com
Thu, 29 Dec 2005 10:24:57 EST


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In a message dated 12/18/2005 4:15:04 PM Eastern Standard Time,=20
robert.scott@tunelab-world.com writes:
Ric, it's not magic.  When struck, the string starts out vibrating only in=20
the up and down direction.  But it quickly precesses into an elliptical path=
, as=20
described by Peter Weinbreck's articles in the 1970=E2=80=99s, and perhaps e=
ven=20
earlier.  Since the string is vibrating both up-and-down and right-and-left,=
 the=20
termination point must be viewed separately in both axes.  If the terminatio=
n=20
point is the same for all directions of vibration, then all is well, and eve=
ry=20
vibration is at the same pitch.  But if the termination point for up-and-dow=
n=20
motion is different than the termination point for right-and-left motion, th=
en=20
these two motions will occur at different pitches, hence the false beat=20
between them.  When a bridge pin is loose, it does not resist right-and-left=
 motion=20
as well as the bridge cap resists up-and-down motion.  Therefore the=20
right-and-left vibration effective speaking length is slightly longer than t=
he=20
up-and-down effective speaking length.  This is consistent w!
ith the =20
observations of performing the screwdriver test for loose pins.

Robert Scott
Ypsilanti, Michigan
_______________________________________________
Greetings,

        This explaination is excellent!  Thank you!

Happy Holidays
Julie Gottshall,
Reading, PA

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