Vibrato Unit - Vibrato or Tremolo?

Vibrato or Tremolo?

The term "vibrato unit" was introduced on high-end Fender guitar amplifiers in the 1950s, starting with the Vibrolux amplifier in 1956, in the same period in which what is now called a "tremolo arm" was introduced on Fender guitars.

The "synchronised tremolo" was introduced in 1955 on the first Stratocaster guitar. The only previously successful "tremolo arm" was the Bigsby vibrato tailpiece, often simply called a "Bigsby". In 1958, Fender reinforced his usage with the "Fender floating tremolo" on the Jazzmaster and some subsequent guitars. The "synchronised tremolo" became the most copied of these three basic patterns of "tremolo arm", although both of the others continue to have some following.

In both the case of the "tremolo arm" and "vibrato unit", Leo Fender had reversed the established usage of the terms vibrato and tremolo. That is, he called a device that produced true vibrato a "synchronised tremolo", and a device that produced true tremolo a "vibrato unit". In fact he was using the terms interchangeably. The first Fender vibrato unit (1954) was called "tremolo", and some later Fender tremolo arms were called "vibrato tailpieces" or similar.

But the terms that became established were "tremolo arm" and "vibrato unit", both contrary to standard usage, with the result that electric guitarists traditionally use the terms "vibrato" and "tremolo" in the opposite senses to all other musicians when describing these hardware devices and the effects they produce. From time to time it is proposed that this should be corrected, and the term "tremolo arm" rejected in favor either of "vibrato arm" or of a neutral term such as "whammy bar", but there is no corresponding "correct" term for a vibrato unit.

The task of producing a similarly "correct" term for a traditional vibrato unit is slightly complicated by two factors:

• The subsequent development of other guitar effects units such as chorus effects, phasers (sometimes called phase vibrato units) and flangers, which can be set to produce changes in pitch similar to traditional vibrato as understood by most musicians.

• The fact that, under harmonic analysis and contrary to the expectations of many musicians, the output of the original vibrato unit does contain other frequencies near that of the note frequencies and in place of the note frequencies. These are the mathematical result of the variation in volume of the notes, so there is a slight sense in which Leo Fender was correct in his naming of the vibrato unit (but not of the "tremolo arm").