Re: Bends: physics and physical

["Oliver Schoenborn" <oliver.schoenborn@xxxxxxxxxxx>]

Sorry if this has already been mentioned, but you may find similar physics
analyses at www.turboharp.com.
Cheers,
Oliver


> Bends are due to the player altering the resonant frequency of the
> vocal tract.
>
> The typical blues harp bends rely on the interaction of the two reeds
> in a chamber.
>
> The higher note in each channel can be bent to a pitch slightly above
> that of the lower note in the same channel.
>
> At the furthest extent of the bend, the note is being produced almost
> entirely by the low pitched reed operating "backwards" (ie, in a full
> draw bend, it is the blow reed which is mostly contributing to the
> tone and vice versa).
>
> Overblows and overdraws work very similarly to "normal" bends. During
> an overblow, the blow reed in that channel is mostly inoperative and
> it is the draw reeds that contributes mostly to the note, sounding at
> a pitch a little above its "normal" one. This pitch can be bent
> upwards.
>
> The lower note in each channel can also be bent, but only by a very
> small amount before the reed stalls and the overblow or overdraw kicks
> in. Valving the opposite reed to prevent the usual interaction means
> that these notes can be bent further, but these bends are different
> from the previously described bends which involve both reeds working
> as a pair.
>
> Erm, I think that's about it!
>
>  -- Pat.
>
>
>
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