[Date Prev][Date Next]   [Thread Prev][Thread Next]   [Date Index][Thread Index][Author Index]

Re: Chambered body on electric guitars

Danish Dave:

>I have noticed that some elctric gutars (Klein, Anderson etc etc)
> have hollow bodies without f-holes (chambered bodies) what
> affect does this have on the sound ??

It improves resonance.  Resonance occurs for single solid objects when they
experience maximum physical vibration for a given input (so a struck string
vibrates at its resonany frequency).  Solid guitars have two main resonance
sources - the neck (which swings up and down like a twnaged ruler) and the
body (which vibrates not unlike a drum head).  The frequency spectrum of
resonance and antiresonance couples with the frequencies (fundamentals and
harmonics) produced by the vibrating string to make a guitar sound more
complex.  This is why really rigid guitars (eg graphite, and to a lesser
degree, maple) have a repulation ofr sounding "sterile" - there is not 
colour to the sound.

Adding tone chambers has two effects - you make parts of the body much 
to vibrate (where the top thins for the tone chamber, you get a miniature
"sound board" effect), and it inroduces the idea of there being several
coupled masses with flexible parts between them (ie the solid bits and the
hollow bits).  Finally, the air gaps actually also haver their own resonant
frequencies.  So a hoollowed out guitar is going to have a far more complex
tonal fingerprint, becahse you have lots of different resonances with lots
of different frequencies.

What happens is that when the string (fundamental or harmonic) frequency
matches a (neck or body) resonance it vibrates the neck or body, which you
can often feel of yuo're holding the part in question.  Since energy is
being lost in driving the body part, it is "sucked out" of the string - 
is known as parasitic energy loss, from string to body (or neck).   Since
you have more resonances (and as the guitar is more flexible, they cause
even more energy loss), you have a lot of dynamic range - some frequencies
are a lot louder than others - and this makes the guitar sound more
"lively".  It also makes the guitar sound more acoustic - resonance in
acoustic guitars is a real mess (since what you hear is the top, back and
soundhole resonating) but is nevertheless based on a similar principle.


(Lecturer in Mechanical Engineering, University of Surrey)