The whammy bar (vibrato bar) is the most powerful sound
altering tool of the guitar. Simply said, there are
sounds you can create "only" with a whammy bar.
Not even the whammy pedal can reproduce the sounds and
feel that are created by an inventive guitarist who may
choose to use this powerful tool.From the grooving sounds
of surf guitar (using minor chords) to gashtly hallows of
Heavy Metal .
Early inventions included the Bigsby which could be found
on the Epiphone ES-295 which was introduced in 1952 by the
legendary Scotty Moore who was Elvis Presleys guitarist.
The Bigsby is a large spring operated system which is
mounted on top of the guitar body. In the 70's, Floyd Rose
introduced the "locking" whammy system, where the springs
were mounted underneath, inside the body of the guitar.
PS: this is not MY explanation...