longitudinal mode vibrations

[Richard Brekne]

> Richard Moody wrote:
>
> > Hi Jim,
> >         Since no one asked, what are longitudinal mode vibrations?  How is it
> > detected?  Can it be measured?  Is there an audible quality to it other
> > than false beats?.  Is this a phenom. of bass strings? Is this caused by
> > the vibrations of the sound board, so that it would appear after the first
> > second? Maybe I have been glancing too fast over the discussions on this,
> > but once the sound board is set into motion doesn't that affect the way
> > the string vibrates? (which set the sb in motion to begin with?) Is this
> > what LMV is about?
> >
> > Ric V's
> > -
>

Now I have been around the net to about 20 different universities looking at what
their physics departments had to say about transverse and longitudinal waves as they
relate to music instruments. What I can gather is that you can describe transverse
waves as standing waves (Stretch a rubber band between to fingers and pluck it, the
wave goes up and down) and longitudinal waves are traveling waves, (take a peice of
rope and give it a whip, watch the wave move away from you)

The thing I dont quite understand is that Longitudinal waves are not really supposed
to appear in fixed strings as there are two fixed end points which prevent the wave
from traveling. Does this mean that piano wire is not so fixed in length after all ?

Richard Brekne