As a professional percussionist, I can tell you that when percussionists
talk about a marimba that is bought, sold and made today, they are
basically talking about an instrument of range anywhere from 3 to 5
chromatic octaves (4 is most common, but the new trend is going down
towards 5 octaves), with resonators and _without_ the buzzing
membranes.

The marimbas with buzzing membranes are most commonly referred to as
"Mexican" or "Guatemalan" or even "buzz" marimbas.  They can range from
a simple diatonic scale to a full 5 chromatic octaves.  To quote Vida
Chenoweth's book, "The Marimbas of Guatemala", she states:

 "Characteristic of the Guatemalan marimba is a slight buzzing sound,
  called charleo, which accompanies the notes as they are played.
  This sound is produced by a delicate membrane, taken from the
  intestine of a pig, that covers a small aperture located near the
  bottom of each resonator.  The membrane is attached to the resonator
  with a circle of beeswax. ...

 "To the Guatemalans the charleo is an extension of the marimba's tone
  and is viewed as an integral part of it's tone quality."

Although I, personally, have heard the membrane referred to as a "tela",
and I have heard of monkey intestines and even spider webs (don't ask
me how!) used for the buzzing membranes as well.

It is interesting to note that in the 1920's there were several
Guatemalan marimba bands traveling and recording in the USA with
their buzz marimbas.  J. C. Deagan tried to capitalize on this and for
awhile produced a modern marimba (well-tuned, chromatic, with metal
resonators) that had a buzzing membrane attached to the resonators.

Deagan called this instrument a "Nabimba".  It was not a big seller,
however, and they eventually discontinued this instrument.  Other than
that, every company that I'm aware of that made marimbas in the USA
made them without buzzers.  Whether one likes the buzzing or not is an
individual choice.  I believe each has it's own unique charm.

Metal bar instruments are most commonly either orchestra bells
(sometimes called a glockenspiel) or a Vibraphone.  The orchestra bells
sound two octaves higher in pitch than a Vibraphone.  The celesta is a
metal keyboard operated instrument usually played by the pianist in the
orchestra.  There _is_ also such a thing as a keyboard glockenspiel,
but they are seldom used anymore.

Wooden [orchestra] instruments are usually either a xylophone or a
marimba.  The main differences are that the xylophone sounds one octave
higher in pitch than the marimba and also, very important, they are
tuned a bit differently.  Each xylophone note is tuned so that you hear
the octave and a fifth partial, called "Quint-tuning".  The marimba is
tuned so that you hear an octave partial.  Mostly softer mallets are
used on the marimba, helping to give it a more mellow tone.

That's how those instruments are viewed in the percussion world.  As
far as percussion in theater organs, player pianos and music box things,
I don't know what they are called -- you are on your own!

Danielle Squyres

 [ "The Marimbas of Guatemala", by Vida Chenoweth; Kentucky:
 [ University of Kentucky Press, 1964.  More about Ms. Chenoweth at
 [ http://marimbavidachenoweth.com/  Thanks for the performer's
 [ perspective, Danielle, and the mention of Vida Chenoweth; I think
 ] I'll buy the book!  :-)  -- Robbie