RE: Klein Electric Guitar

[matthias@bahianet.com.br (Matthias Grob)]

Tom Attix said:
>What about the feedback of the (body) vibration from the acoustic
>chamber to the string? Obviously, you can't increase overall string
>vibration (amplitude) by coupling it to an acoustic chamber but could
>the chamber act as a "storage device" for resonant freq's thereby
>sustaining certain harmonics (longer than they would have been
>originally) and effectively dampening nonresonant harmonics? If you plug
>this into an amp, it will feedback much easier (energy is never free but
>maybe you can get it a little cheaper...).

Certainly the acoustic chamber works reverse: if it makes the instrument
sound louder acoustically, it also transferes sound easyer from outside
onto the string and thus feedback happens easyer.

If I understood right, you think that even unpluged, some harmonics could
be sustained more than without chamber. This would mean that the energy of
the frequencies that are dampened is transfered to the sustained ones. I
never thought of this, but it seems to make sense... I think I heard a
similar effect from gongs, or was it just my impression that the high
frequencies increase (absolutely, not just relatively to the low ones)
after the initial rather bassy attack? Anyone can confirm that? (I have no
gong :-( )
Still, to achieve this certainly takes a master lutier!


Kim Corbet wrote:
>......well, it seems to me "acoustics" differs from this point of view.
>the string vibrates...the chambers resonate.  It's the amplification
>properties of the chambers themselves that create the sustain.  Take an
>acoustic guitar without the huge box and you haven't got much.  Play any
>hollowbody guitar vs. solid body...play through any good quality speaker
>cabinet and then through a speaker sitting on the workbench and you start
>to appreciate what "chambers" can do.

I felt that the solid body guitars have the most sustain (unless they are
not built well or intentionally dampened and the string energy transforms
into heat). The chamber only increases sustain at the resonant frequency.
It does not really amplify, it transforms acoustic impedance: The strong
movement of the little surface of the string is transformed into a little
movement of a big area.
The Banjo transforms all string energy soon it to a loud and consequently
short sound.

The speaker cabinet prevents from a acoustical short cirquit between the
area in front of and behind the membrane. Sustain what you least want for a
speaker, or it will loose all definition.

Matthias