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
> -

TYPES OF MECHANICAL WAVE MOTION
Transverse waves cause medium displacements perpendicular to the direction of the
propagation of the wave.  Example:  Wire vibrating under tension.
Longitudinal waves cause medium displacements in the same direction as the
propagation of the wave.  Example:  Vibrating column of air in a tube.

Intensity is the power per unit area of a sound wave emanating from a point
source and varies as the inverse square of the distance.

The intensity is a function of the properties of the medium, the frequency of the
sound, and the actual amplitudes of the molecular motions.
Speed of propagation is dependent upon the nature of the material.
* Strings (Transverse):  Tension (F), mass per unit length
* Gases (Longitudinal):  Temperature, molecular mass

Richard Brekne