One of the earliest guitar effects built into early guitar amps was the Tremolo and Vibrato effect. Although the terms are used interchangeably, technically Tremolo is an up and down pattern of volume and Vibrato is an up and down patter of pitch. These effects occur almost naturally in the singing voice and are taught as a natural part of playing violins, violas, cellos and saxophones.
Rotating Speaker Tremolo and Vibrato
For electronic organs, the tremolo/vibrato effect was often generated by the use of a rotating speaker called a Leslie. The rotations cause both a tremolo and vibrato because the motion of the speaker had the effect of altering the volume depend on direction and altering the pitch by means of the Doppler effect.
Tremolo and Vibrato in 1960s Amps
Aside from the Leslie rotating speaker, the original effects built into amps were not very subtle. In the 1960s guitar amps typically had simple tremolo and/or vibrato effects that produced a very noticeable loud soft pattern. Most of these amps could turn the effect on and off with a footswitch, change the intensity of the effect with a knob, and occasionally speed or slow down the effect. Today’s Tremolo/Vibrato Pedal Effects can do quite a bit more and can be equally noticeable or much more subtle as needed.
Top Choices in Tremolo, Vibrato, and Leslie Speaker effects
For example, look at what these pedals do:
The TC Electronic Shaker Vibrato includes a classic true pitch vibrato capable of adding a Leslie speaker effect to guitars, voices, and whatever. You can control the speed and depth of the effect and its timing (how long it takes to start after you engage the pedal). It has a USB connection that lets you download custom tunings made by and ever expanding roster of fine guitarists. You can also use this pedal to get whammy bar effects. Being a product of TC Electronic, this pedal has some of the finest circuit design available and of course true-bypass.
The DigiTech HardWire TR-7 Tremolo Rotary Vibrato Pedal is one of the most versatile pedals in this category. It can produce seven effect types including Rotary (Leslie Speaker) effect and classic Fender and Vox vibrato and tremolo effects. You can have interacting dual synchronized tremolos, variable waveform tremolo, and panning vibrato. The Digitech Hardwire Tremolo is a true stereo unit with stereo inputs and outputs and has true bypass circuitry.
The Boss RT20 Twin Rotary Guitar and Keyboard Pedal produces one of the most authentic Rotary Speaker simulations. Using Roland’s proprietary COSM sound modeling technology reproduces all details of the classic rotary speaker design including adjustable rise time, horn speaker speed, and bass speaker speed. You get overdrive effects, pulsating effects, and even a classic Univibe effect.
Many players just want to keep it simple with the Boss TR2 Tremolo Effect Pedal. You can control waveform, rate, and depth of this classic tremolo effect. The sound is just what you would get from the built in tremolo on a vintage guitar amp from the 1960s.
The Pigtronix Tremvelope Tremolo Effect Pedal is an example of the LFO controlled Auto Wah. With its envelope follower switched off the audio path is modulated by a Low Frequency Oscillator with speed, depth, and waveform controls, for a versatile Tremolo effect with stereo panning. With the Envelope control switched on the tremolo is controlled by the dynamics of your guitar playing. The sound is akin to what you get playing through a rotating Leslie speaker, but with continuing changes in rate and depth.