Acoustic resonance in harmonica covers

[Samuel Gravina <sgravina@xxxxxxxxxx>]

Michelle LeFree wrote:

> ... The top-to-bottom inner dimension of the Turbolids are ~designed~ to
> be greater on the "left" end of the harp where the low notes are produced
> than the "right" end where the high notes are generated.  In this way, the
> T'lids are designed so that the inside dimensions of the cover are "tuned"
> to the wavelength of the notes created by the reeds directly beneath them.

On a C harp 3 draw bent is an A, 220 Hz.  The speed of sound is 335
meters/second.  That makes the wave length of that A note 335/220 = 1.5
meters or 4 1/2 feet!  Lower notes have an even longer wave length.
Acoustic resonance is not occurring in harmonica covers.  The dimensions
don't fit.

My understanding of the fat bottom end was so that low reeds wouldn't hit
the harp covers which happens on some low tuned harps.  It happens on my
Steve Baker Special in D on the lowest reed.

Sam