Harmonic tremolo is one of the oldest effects yet not many people know about it. In this article we explain what it is and give an overview of the 10 best harmonic tremolo pedals of the moment.
Origin of the tremolo effect
The first tremolo effect unit is probably from DeArmond and dates back to the early 1940s. Beginning in the 1950s, Fender incorporated the effect into its Tremolux and Vibrolux amplifiers. Fender called this effect ‘vibrato’ and was therefore partly responsible for the confusion of tongues that still exists between tremolo and vibrato.
To understand harmonic tremolo it is good to first dwell on the tremolo part and then explain the harmonic part later.
What is tremolo?
Simply put, tremolo is a constantly repeating variation of volume of sound. The sound becomes louder and softer in a pattern that repeats itself continuously. There are three main parts to this description:
constantly repeating – tremolo effects use a low frequency oscillator (LFO) waveform to modify the audio signal. This can be a sine wave, but other waveforms are also possible. The waveform takes a certain amount of time before it starts again. The time of a full wave determines the speed of the effect.
variation – the LFO has a certain shape and this shape determines how the volume increases and decreases. With a sine wave, the volume of the signal gradually decreases and also gradually increases. With a square wave, the volume abruptly decreases or increases abruptly in certain places.
volume – the LFO has peaks and valleys and the height of these peaks and valleys causes the volume to rise and fall. The higher the peak – the louder the signal, the lower the valley – the softer the signal.
What is harmonic tremolo?
To turn a tremolo into a harmonic tremolo, the audio signal must be split into high and low frequencies. Both branches of the signal then pass through a tremolo, creating volume variations in the treble and bass.
If these variations happened at exactly the same time – the peaks and troughs of both waves are the same size and come at the same time – you would hear a normal tremolo. That does not happen, the peaks and troughs of the two waves are switched ‘out of phase’. This means that when one wave has a peak, the other has a trough and vice versa.
The result of this is a very lush and quite unique form of modulating sound. In the distance it looks a bit like a uni vibe.
The 10 Best Harmonic Tremolo Pedals
Below you will find an overview of the 10 best harmonic tremolo pedals of the moment.
Walrus Audio Monument V2
What do we like about it?
- great sound and very musical
- lots of different lfo shapes
- many setting options
- tap tempo
- expression control
Jam Pedals Harmonious Monk
What do we like about it?
- both vintage and intense effect
- unique intense effects to our ears
- extra footswitch controls 2 speed options
- many setting options
JHS Pedals Harmonic Trem
What do we like about it?
- super simpel pedal
- excellent price/quality
- 2 types of tremolo
Chase Bliss Gravitas
What do we like about it?
- many options, including ramping, toggle switches
- sounds excellent
- tap tempo
- expression control
- MIDI controllable
Earthquaker Devices Night Wire V2
What do we like about it?
- unique pedal
- dynamic tremolo effects reacts to attack of your playing
- speed can also reacts to attack of your playing
MXR Tremolo M305
What do we like about it?
- 6 different tremolo modi, we like Harm-style
- expression control
- stereo
Strymon Flint V2
What do we like about it?
- 3 classic tremolo effects and 3 reverb effects in 1 pedal
- Strymon quality in sound and build
- stereo
- expression control
- True of Buffered Bypass
- MIDI controllable
- 300 MIDI accesible presets
Anasounds Ages
What do we like about it?
- loads of options for adjusting effect
- both speed and depth can react to playing style
- self-oscillating loops
- tap tempo
Keeley Hydra
What do we like about it?
- both tremolo and reverb pedal
- hi-fi sound quality
- stereo
- tap tempo
- 3 presets
- both true and buffered bypass
Source Audio Vertigo
What do we like about it?
- 3 different, excellent sounding tremolo effects
- loads op options, expandable through Neuro App
- stereo
- MIDI controllable
- 128 MIDI accesible presets
For more information: this page from Anasounds contains a technical explanation of the harmonic tremolo effect.