PHOTO: Detail from Leo Fender's 1956 patent for a "Tremolo Device for Stringed Instruments".
They're similar, but they're not the same.
By Jeff Owens
Let’s address an age-old quandary in the guitar and amp world, namely, the use of the terms tremolo and vibrato.
These two words are often used interchangeably, but in fact they aren’t the same thing. Tremolo and vibrato are two separate and different physical and acoustic concepts, and people sometimes say one when they actually mean the other.
The main reason why is that for decades, guitar and amp makers—Fender included—have labeled the mechanisms of vibrato-equipped guitars as tremolo systems and, more often than not, labeled amps built with tremolo circuits as vibrato-equipped devices.
Basically, it shakes out like this:
Vibrato is a pulsating sound effect produced by slight and rapid changes in the pitch (frequency) of a note. It has been used for centuries as a technique for adding expression and coloration to music, and it is characterized by two parameters, depth (the amount of pitch variation) and speed (how quickly the pitch is varied).
Tremolo, on the other hand, is a trembling or “shuddering” effect produced by slight and rapid changes in the volume (amplitude) of a note. It, too, has existed for hundreds of years as a musical technique, but for our purposes it is a much more recent technical innovation used in amplifier design. It is characterized by similarly labeled parameters, including depth (the amount of volume variation) and speed (how quickly fluctuations in volume are varied; also variously labeled as rate or intensity).
In short: Vibrato deals with change in pitch. Tremolo deals with change in volume.
True vibrato is most often achieved either manually or mechanically. Manual vibrato (“hand vibrato” or “finger vibrato”) is a fingerboard technique in which the fretting hand bends the string up and down smoothly and regularly, thus producing the slight alterations in pitch by which vibrato is correctly defined. Since the mid-20th century, many electric guitars have been equipped with mechanically operated vibrato systems, most often in the form of a rocking bridge assembly operated by a hand lever.
Therein lies the confusion. When Fender introduced the Stratocaster guitar in 1954, the guitar was equipped with an ingenious mechanical bridge mechanism designed to efficiently enable string bends from subtle to swooping while maintaining accurate intonation. This was in actuality a vibrato system, but Fender billed it, in a non-standard use of the term, as a synchronized tremolo system. Indeed, one of the very first Strat advertisements in 1954 led with the headline Tremolo Action.
Ever since, Fender and guitar players worldwide have referred to the mechanical vibrato systems of the Stratocaster, other Fender guitars and electric guitars by a variety of other manufacturers, as tremolo systems. The common name for the lever arm that operates these systems has long since passed into the guitar lexicon as the trem arm, and other parts are similarly labeled (i.e. trem block, trem springs, etc.). Make no mistake, however—the phenomenon these devices produce is vibrato.