Tremolo = Change in Volume
Tremolo is an effect created by a consistent alteration of the amplitude, or volume, of the guitar's sound signal.
Tremolo is one of the oldest guitar effects and was available on many early electric guitar amps. Tremolo effects soon started becoming available in stompbox form to allow for more tempo control and other options.
Tremolo is similar to turning the volume knob on your guitar up and down slightly or dramatically while sustaining a note or chord. The tremolo rate can be adjusted so the duration of time causes the sound to slowly fade in and out, or chop up the sound signal into increments of full volume to no volume.
The “Tremolo” Arm
The term “Tremolo Arm” refers to a vibrato system for an electric guitar. This term is incorrect however, as it creates a vibrato effect rather than tremolo due to the string tension moving up and down. The tremolo arm is also known as a whammy bar, credited to Lonnie Mack and the song “Wham!” released in 1963.
Vibrato = Change in Pitch
Vibrato is similar to tremolo, but instead alters the signal's pitch, not the volume, at a set speed similar to bending a guitar string slightly over and over. This effect can be achieved using a stompbox or pedal, but is commonly used with electric guitar vibrato systems.
The Bigsby Vibrato Tailpiece, or just Bigsby, entered the market in the tail-end of the 1940s on Bigsby electric guitars. It soon started being used on Rickenbacker, Gibson, and Gretsch guitars. The Bigsby was the first electric guitar vibrato system to have success on the market and helped pave the way for other vibrato systems.
The Fender Synchronized Tremolo was introduced on the 1954 Fender Stratocaster, the first Fender guitar to use a vibrato system.
Using tension created by springs in the body of the guitar connected to the guitar’s bridge, the Fender Synchronized Tremolo, or “Strat Trem” bends the pitch of the notes. This was done using the falsely named tremolo arm, which was the term used to market the Strat.
Fender later introduced a different type of vibrato system called the Fender Floating Bridge on guitars like the Fender Jazzmaster and Fender Mustang.
The Floyd Rose Locking Tremolo was created by Floyd Rose in 1976 and made famous by guitarists such as Eddie Van Halen, Steve Vai, Joe Satriani and many others.
The Floyd Rose uses the basis of the Fender Synchronized Tremolo with a few added mechanisms that allow the strings to lock. Floyd Rose had trouble with another vibrato system he was using on his guitar as it went out of tune frequently. By locking the strings, the Floyd Rose lets you alter the pitch drastically without the guitar going out of tune when released to the normal position.