Natural Science Forum / Physics / Acoustics / July 2007

It has hundreds. Your best bet is always to measure, because the way
it is fitted will have its own impact as well.

d

If you want to predict have a look at  Vibration of Plates by Arthur W.
Leissa, available through ASA.  You will find formulae for thin plates in it
Geoff
____________________________________

    The mecahanical bending modes are easily calculated. See any mechancial
engineering handbook for vibration formulas. The exact frequency depends
on the size of the glass plate and its edge mounting condition (fixed,
or hinged, or free).

    Then there is the matter of the coincidence frequency, about 2 kHz for
common window glass, independent of widow dimensions, dependedent only
of the glass sheet thickness.

    Angelo Campanella

Ron <ryon@quik.com> wrote in news:1184502964.811828.286880
@g37g2000prf.googlegroups.com:

There's no simple exact formula, except for certain ratios of length to
width. They are given in Blevins This assumes the edges are pin jointed. If
you are interested in acoustic transmissibility then Beranek or Harris have
the equations, I think.

Cheers

Greg Locock