Africa was not only the birthplace of man but also the birthplace of many musical instruments and early art forms. The keyboard instruments in the percussion family generally were derived from early balafones such as the one pictured here. These instruments were made of wood, had one register (row of keys), and were never tuned as exact as todays instruments. Pentatonic and other derivate modes were used, but for the most part, not a whole lot of resonance came from the instruments. Eventually the use of resonators became common, and early ones were made of gourds which can be seen on the instrument on the left.
Todays Instruments
The common instruments today in the keyboard area are the glockenspiel (sounds 15ma up), the vibraphone, the marimba, the xylophone (8va up), and the chimes. All are pitched in C, and ranges vary considerably. The glockenspiel (or orchestra bells) have 2-3 octaves; vibraphones have 3-3.5 octaves ; xylophones have 2.5-4 octaves ; chimes have 1.5 octaves. Marimbas probably have the most derivations in size, with 4 1/3, 4 1/2, 4 2/3, and 5 octave instruments. The range on a 5-octave instrument is C to c4. There are bass marimbas which go even lower than the standard C note, but they are not common. The marimba and xylophone are made from [rose]wood bars, where as the other keyboards are made from aluminum or steel bars generally. The marimba, xylophone, vibraphone, and sometimes bells have resonators underneath them. These are basically one-ended, stopped tubes which are capped at a certain length related to the frequency of the bar. They act to enhance volume and resonance. Some resonators are adjustable, which is a plus for wood instruments which go out of tune frequently in adverse climates.
Notice the resonators on the vibraphone here - although arc-shaped, the higher notes' resonators are still capped much higher than the lower notes - one cannot tell where the tubes are capped without looking down them, and the various shapes in resonators are simply aesthetic.
The xylophone
This instrument is the highest pitched of the woden keyboards. It is probably the most used of the instruments in ensembles, but outnumbered by the marimba as a solo instrument. Danse Macabre by Saint-Saens is generally credited as the first piece in orchestral music to use the xylophone. This lick in Porgy and Bess is probably the most famous excerpt or the piece. The xylophone is usually played with hard plastic, phenolic, or rubber mallets.
The vibraphone
The vibraphone, invented in 1916, is the only true keyboard instrument with a pedal and a motor. The aluminum alloy bars are suspended on a frame like the other instruments but there is a long strip of felt on a dampener which is always in contact with the bars until the pedal is depressed. This instrumentutilize has the purest timbre of the family, being very close to the sound of an overtone-devoid sine wave. The motor on is adjustable for different speeds and gives the instrument its inherent vibrato sound that interestingly is not used that much today. Cord-wrapped mallets with rattan shafts are probably the most common choice for most players and many players utilize the "Burton cross-grip" on this instrument. (see picture) Rolls are not called for much on the vibraphone since the bars ring so long already. Conversely, more dampening techniques are used for this instrument such as mallet-dampening in which the player can mute 1 note of a chord by sliding a mallet over it after it has been struck.
Orchestra bells
The better bells are made from steel, and ring for a long time. Parsifal bells, the sister-instrument, are very similar except they have resonators. The opera Magic Flute by Mozart was probably the first work to use the keyboard glockenspiel. Often times, a celeste or other instrument was used. Sometimes, the bell players gets these celeste parts which can be very difficult, especially when extended ranges are called for. One of the biggest difficulties in orchestral excerpt transposition problems is with this instrument. This instrument uses plastic, acrylic, wood, brass, and sometimes rubber mallets. Any time a brass mallet is used anywhere, it should be played softly since they can dent the bars and put them out of tune. Hand muffling is often used to eliminate the clusters of sound produced by fast passages with this instrument.
The marimba
This instrument has come to a rise in popularity n the last few decades. It is probably the foremost solo instrument for the keyboard percussionist and covers a wide range of tones and pitches. It has rosewood bars like the xylophone although more wood is cut away from the undersides of the bars on a marimba. Synthetics are available for both instruments, and are better for outdoor/high school use. However, they tend to sacrifice the real sound of the instrument and often, the synthetics actually tend to ring too long. All kinds of mallets, minus the hardest plastics and brass ones are used on this instrument. Usually though, for solo work, yarn mallets with birch shafts are used. The rattan shafts on vibraphone are generally too forgiving and bend to easily. THe grip is also not as conducive to using birch. The standard grips are the traditional, Stevens, and Musser grips. The traditional grip is like the Burton cross-grip except the outside mallets are not the closest to the palm. The other grips utilize no cross and although a greater range is attainable, power is lost with this grip. However, this instrument generally doesn't get played as hard as the vibraphone. This excerpt shows the how the marimba has even infiltrated the jazz scene, and can be combined with instruments such as steel drums.
