Additive synthesis rendered Harmless!

Harmless performs subtractive synthesis using an additive synthesis engine, but why? The subtractive-additive process can create sounds that are simply not possible or if they are, tediously complicated to program using subtractive synthesis alone. With Harmless, filters and phasers can be assigned unusual shapes and slopes, the slopes can even be defined in Hz resolution instead of octaves. Finally, Harmless gains control of each partial's frequency, opening a world of new possibilities for creating innovative sounds. But all that is just detail, put simply, Harmless is a ground-breaking subtractive-additive synthesizer that sounds amazing, has a huge repertoire and invites experimentation, as you are about to discover.

Check the Harmless video series Image-Line | Harmless (VST & Native Plugin Instrument) or Harmless forum here.

Click on the screenshot above to jump to the help for that section

NOTE: The Harmless GUI color codes knobs and sliders so that related controls are the same color. We recommend loading a Wave Candy Spectral Analyzer after Harmless while you are learning to program the plugin, a picture is worth 1000 words, so they say.

Harmless Key Features

The Harmless design philosophy is 'less is more', every feature, control and harmonic function was carefully selected for maximum effectiveness. LESS HARMonics, now that's Harmless!

For more detailed information on programming Harmless, see the Tutorial section.

Main Controls

Harmless is a single page synthesizer making fast program changes simple and is perfect for live performances and experimentation. The five main control categories are:


The Oscillator (audio source) is controlled by the Timbre selector. Choose from a range of waveform shapes. The oscillator is based on additive synthesis, that is a fundamental or root pitch and its harmonics are added to create more complex waveforms. Most of the built-in waveforms are bright, rich saws since other common waveforms, like pulse, are created by filtering. A pulse can be generated through the harmonic mask or even with the phaser. The additively generated waveforms are calculated according to the following controls:



NOTE: The default polyphony is 16 voices (see the Miscellaneous Channel Settings).


The filter functions control the type of filtering and cutoff frequency. Envelope and LFO functions are added to the filter cutoff frequency as set by the freq control.


Unison is a thickening and stereoizing effect, similar to chorusing. Unlike chorus, that is applied to the final output, unison is a per-note effect where each note is given a user-defined number of 'subvoices' (from the order setting). Subvoices are then given user-defined variations of panning, volume, pitch and phasing relative to the root note as per the following controls:


Phasing is the process of creating, constantly moving, frequency cancellation/s in a sound. The Harmless phaser allows individual harmonics to be phased rather than it being applied to the entire output or 'cancellation patterns' (cut templates) to be applied to the timbre making a range of interesting phasing and harmonic effects possible.


The harmonizer clones the existing harmonics upwards, using various methods (+ octaves, or by an offset).


The LFO (Low Frequency Oscillator) is a generic modulation source that can vary the value of a number of target parameters on the Harmless interface including;

Look for the lfo knob under the controls to be modulated.


The integrated effects are designed to be easily tweaked and not distract you from the task of making music or sound-design. If you want more complex effects then use external plugins following Harmless in the Mixer chain. If you do this, keep an eye on the effects already in use on the patch so that you don't double up on reverbs or delays, unless that was your plan.

CPU options

The switches to the right of the effects section provide options to trade audio quality for CPU efficiency.

About Harmless (?)

Special note colors

The native FL Studio version of Harmless responds to MIDI note colors 14, 15 and 16 as follows:

NOTE: Click on the colors OR text to select.

Plugin Credits

Code & GUI: Didier Dambrin.