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!

  • Additive-Subtractive engine providing unique capabilities.
  • Single page color-coded GUI for immediate gratification.
  • Efficient CPU usage & multithreading.
  • Harmonic mask function.
  • Specialized pluck filter.
  • Unique phaser & harmonizer

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:

  • Timbre - The oscillator or sound generation controls.
  • Unison - Voice thickening & stereoizing effect.
  • Phaser - Creates totally unique phasing and partial based effects, only possible with Harmless.
  • LFO - Modulation source for adding motion and evolution to sounds.
  • Effects - Chorus, Delay, Reverb & Compression.


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:

  • Timbre - Select from a number of pre-computed additive waveforms. NOTE: The Custom timbre option will open a browser to load and resynthesize a single-cycle waveform audio file to import the timbre. Once loaded, selecting another timbre and returning to the Custom value will now open the new customized waveform as a preset. Right-click to reset the Custom timbre:
      Right-click menu - To select from 'Analyze single cycle waveform' browser and 'Reset custom timbre color'. NOTE You can drag waveforms from within FL Studio (from anything that supports drag and drop) onto the Harmless GUI to be analyzed as a Custom timbre.
  • phase - Turning left randomizes the phase of each harmonic separately. This is useful for creating 'metallic' timbres. Turning to the right sets the global waveshape phase to a 'free-running' mode. This is useful to add some variation to transients in the timbre.
  • lhp - Low Harmonic Protection. Prevents filtering functions (harmonic mask) from removing the first few harmonics, that are essential for producing the fundamental pitch/tone of the patch.
  • sub - Sub Harmonics add bass, weight or depth to the sound. The first slider Sub 1 is an octave below the root note. The remaining two sub sliders are harmonics of Sub 1. Sub 3 is the 3rd harmonic and Sub 4 is the 4th harmonic. Relative to Sub 1, the 2nd harmonic is the root note, masked by harmonic mask slider #1.
  • equalizer - 6 Band harmonic equalizer. Unlike a traditional EQ this is a floating equalizer, relative to the root note (fundamental frequency). For example the first slider will always affect the 1st harmonic and a little of the 2nd.
  • harmonic mask - Sliders cut the harmonics from the Timbre waveform. Sliders 1 to 12 relate to the first 12 harmonics of the root note and frequencies that are multiples of 12 for each slider up the harmonic frequency scale. In other words, the harmonic mask is a repeated stamp over all harmonics, cutting where selected. Generally the mix control must be active for the mask to have an effect, however a positive and active LFO can override that. To hear the harmonic mask, select the default patch, turn the lhp and sub harmonic sliders to their minimum settings, minimize all the harmonic mask sliders and turn the mix knob fully clockwise to hear only the masked signal (i.e nothing should be audible yet). Then raise each harmonic mask slider in turn and listen to the result. These are the individual harmonics and their 12x multiples.
  • mix - Change the harmonic masking level (to disable turn fully left).
    • lfo - Subjects the mix level to LFO modulation. Turn left to modulate cut harmonics and right to modulate active harmonics. The lfo characteristics are under the control of the main LFO controls (lower right on the interface).
  • trem - Stereo tremolo effect. This is a left/right panning of the sound that simulates the rotary speaker effect used in some classic organ patches.
  • att - Combination of note starting level and attack time. The first few ms of the att knob range adjust only the attack 'starting level' then higher values adjust attack time.
    • VEL - Links note-on velocity to the attack time value.
  • dec - Note decay time.
  • rel - Note release time.
    • VEL - Links note-off (release) velocity to the release time value.
  • pluck - The pluck feature is a specialized, quickly decaying, low-pass filter envelope applied to the timbre.
    • masked - Applies the masking function to the pluck. I.e. mask sliders determine the decay time of the corresponding harmonics. See the tutorial patch 'Masked pluck'.
    • alt - In Alternative mode, the timbre EQ affects the per-harmonic decay speed.
    • release - Pluck only on release. Make sure to use a long decay setting otherwise the effect won't be audible, but not so long you drive up the polyphony and eat CPU.
    • VEL - Links note-on velocity to pluck decay time. When activated the pluck knob sets the maximum release time.


  • vol - Main output volume.
    • VEL - Links note-on velocity to note volume.
  • pitch - Pitch control (+/- 24 semitones).
  • detune - Harmonic tuning. Changes the pitch of the harmonics (+/- 24 semitones)
  • grit - Adds a 'metallic' grittiness by selectively detuning harmonics.
  • vib - Vibrato effect. Fast pitch modulation. TIP: It can be useful to link the aftertouch to this knob. In FL Studio, press & hold a note, Right-click the knob to open the remote control settings and then press the note harder and you are done.
  • lfo - Applies LFO to the main pitch. The value can be positive or negative depending on the direction of the lfo knob.


  • porta - Portamento slides between the levels/pitch of the last note & the new one. time knob determines the slide time.
  • legato - Legato is a monophonic mode and slides between overlapping notes. The time knob determines the slide time.
  • time - Controls the porta and legato slide times.
    • VEL - Links note-on velocity to portamento or legato attack time, and note-off velocity to legato release time.

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.

  • alt - Alternative, 'adaptive envelope' mode ensures the filter cutoff frequency is only modulated over the range from the current cutoff value to the max/min frequency limit. The cutoff modulation range is 'adaptive' in that 100% envelope modulation always = max/min frequency. Direction depends on the amt value being positive or negative. The purpose is to avoid 'pauses' that can happen in 'normal' mode when the cutoff is modulated above or below the max/min frequency and the cutoff pauses at the limit until the modulation value returns to within the audible range.
  • att - Attack time.
    • Attack slope - The knob below the att control determines the shape of the attack ramp.
  • dec - Decay time.
    • Decay slope - The knob below the dec control determines the shape of the decay ramp.
  • amt - Filter cutoff frequency envelope amount. Turning right applies positive modulation of the filter cutoff frequency. Turning left applies a negative modulation of the filter cutoff frequency. In 'normal' mode the envelope is multiplied by the amt value and added to the filter cutoff freq. See alt mode above.
  • VEL - Links note-on velocity to filter envelope amount.
  • lfo - Applies LFO to the filter cutoff value. The value can be positive or negative depending on the direction of the lfo knob.
  • kb.t - Keyboard tracking. Applies an offset to the filter cutoff value depending on pitch. The offset-value can be positive or negative depending on the direction of the kb.t knob. For example, keyboard tracking is useful to make a sound brighter, by raising the cutoff frequency of a low-pass filter, as higher keys are played.
  • width - Filter bandwidth. Narrower widths create a more clearly defined 'center frequency' sound.
  • freq - Filter cutoff frequency. This is the target for all controls in green to the left of the knob.
  • Filter type menu - Choose from cutoff slope variations, crude being the steepest:
    • Low pass - Filters frequencies above the cutoff frequency.
    • Band pass - Filters frequencies either side of a central band.
    • Band stop - Filters frequencies inside a central band.
    • High pass - Filters frequencies below the cutoff frequency.
    • Phaser - 'Comb filtering', a series of stacked band-stop filers.
  • oct / Hz - Sets the filter shape to an Octave or Hertz scale. Set by ear.
  • res - Filter resonance. This boosts frequencies around the cutoff value (depending on the offset value). Resonance accentuates the cutoff frequency position making a familiar 'resonant' sound.
  • Resonance type menu - Choose from resonance type variations:
    • Classic - Single narrow resonance peak.
    • Spring, Pedestal, Sedge hat, Wide bump & Double cone - Various resonance peak shapes, named according to their approximate shape.
    • Well & Wormhole - Cut frequencies at the cutoff frequency with resonant peaks either side of the hole. These settings are designed to be used with the self-oscillation, to avoid annoying interferences and overly loud ringing when the resonance peak passes harmonic frequencies.
    • Noise - Special effect. Randomly selects harmonics to play. Use the res knob to control the number of harmonics selected and ofs (offset) to control randomization speed.
  • oct / Hz - Sets the shape of the resonance frequency peak to an Octave or Hertz scale. Set by ear.
  • ofs - Shift the resonant frequency +/- 2400 cents, relative to the cutoff frequency. NOTE: Resonance may become inaudible if the offset moves the peak past the filter cutoff point, since there may be few or no frequencies to resonate there.
  • osc - Self-oscillation level. A sine wave is deliberately introduced at the resonant frequency developing more distinct 'tonal' sound. Can be useful when the offset moves the resonant peak beyond the filter cutoff point (see 'ofs' above).
  • motion.t - This works with the self-oscillation (osc) feature so that the self oscillation only happens when there is cutoff-frequency motion.
  • adaptive - Adaptive resonant-peak width. The resonant peak changes width as a function of cutoff frequency. Set by ear.


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:

  • Order - Number of unison voices. NOTE: Limit use of high unison orders where CPU load is a concern.
  • Unison type menu - Select from three variations of pitch and panning spread (Classic, Uniform & Blurred). Set by ear.
  • pan - Panning variation across the unison voices.
  • pitch - Pitch variation (detune) across the unison voices
    • VEL - Links note-on velocity to pitch variation.
  • phase - Timbre starting phase variation across the unison voices.
  • var - Adds a offset the LFO position (phase) and phaser speed for each unison voice.


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.

  • amt - Amount of phasing.
  • Phaser type menu - Select phaser type. There are three broad categories as follows:
    • Classic, Triangle, Eggs - In this group you will find settings similar to traditional phaser sounds.
    • Deep, Deeper, Condom, Twins, Cascade & Box - Are special phasing effects that fully exploit the Harmless additive architecture.
    • freq - Extra special! Modulates the frequency of all the partials in the timbre.
  • Phaser scale - Set the scale to octave, Hz or harmonics. Set by ear. See the tutorial preset 'PWM' to learn how to use the phaser in harmonic scale in order to achieve pulse-width modulation (PWM).
  • width - Wider settings cause a more aggressive phase cancellation.
    • lfo - Subjects the width setting to LFO modulation. The lfo characteristics are set at the main LFO (lower right on the interface).
  • ofs - Offsets the phase mask (cancellation) position.
    • lfo - Subjects the offset setting to LFO modulation. The lfo characteristics are set at the main LFO (lower right on the interface).
  • speed - Speed with which the phase cancellations are swept across the spectrum.
  • kb.t - Keyboard tracking adds an offset to the amount control depending on note pitch note.


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

  • amt - Harmonizing mix.
  • width - Determines how far upward the harmonics are cloned.
    • lfo - Subjects the width setting to LFO modulation. The lfo characteristics are set at the main LFO (lower right on the interface).
    • VEL - Links note-on velocity to width.
  • str - Strength places emphases on the first/early harmonic clones.
  • Harmonization type menu - Choose from various transpositions. Set by ear.
  • Harmonization position menu - Choose the location where the harmonizer is added to the timbre (Pre-filter, Pre-phaser, Pre-pluck, Final. For example, Final vs Pre-filter. Adding harmonizer harmonics Pre-filter means the filter can still remove them. Harmonizing added at Final means the filter will have no effect on the harmonizer harmonics.


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;

    • Harmonic mask mix.
    • Pitch.
    • Filter cutoff frequency.
    • Phaser width.
    • Phaser offset.
    • Harmonizer amount.

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

  • att - Attack controls the time taken for the LFO to reach maximum oscillation. The effect is similar to an attack envelope over the LFO.
  • speed - LFO oscillation frequency. Direction left and right of the vertical position controls LFO phase.
  • LFO shape/source menu - Select from a number of LFO waveforms or special sources. In particular the Special category sources:
    • Filter envelope - Uses the filter envelope shape (as set by att, dec and their associated curve controls).
    • Filter frequency - Value of the Filter frequency knob = LFO value.
    • Voice random - The LFO value changes randomly each time a note is played. The new random value only affects the new note, sustained notes hold their original LFO values.
    • Velocity - Note-on velocity acts as a modulation variable.
    • Pitch - Note pitch. LFO Speed becomes an offset when this is chosen.
  • global - When deselected the LFO restarts for each note played and the LFO is unique to that note. When selected the LFO continuously cycles in the background and all notes share the current LFO value.


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.

  • Chorus - The Chorus effect results from the interaction of delayed copies of the input sound, that are detuned by a small and continuously varied amount. It is called 'Chorus' because it can make a single voice sound like that of a chorus of singers (all slightly out of tune relative to each other) and creates a thick and lush texture. The effect is similar to Unison but operates across all voices rather than per-voice and is much less CPU intensive. Select from
    • Chorus type - Select from a range of different Chorus styles. Set by ear.
    • Mix - Controls the balance between the dry (fully left) and chorused signal (fully right).
  • Delay - Delay is an echo-based effect. Very short values of the delay time controls can produce a 'reverb' like sound while longer time settings are great for left-right 'ping-pong' effects.
    • vol - Controls the level of the delay echoes.
    • fb - Feedback controls the number of delay echoes.
    • time - Controls the spacing between the delay echoes. The control is tempo synced, watch the Hint Bar wile you adjust the time setting (delay values display in beats and beat fractions).
  • Reverb - Reverberation, simulates acoustic spaces. If you clap your hands in a bathroom and in a concert hall, the two sounds will be quite different. In enclosed spaces reflections overlap one another to create a 'reverberant' sound. Consider using delay to create the sense of space rather than reverb in a dense musical mix.
    • Reverb type - Select from a range of room sizes.
    • Vol - Volume controls the strength of the reverberant sound.
  • Comp - Select from compression, limiting and distortion effects. Harmless uses the Maximus compression engine.
    • Compression type - Compression increases the low-level parts of the sound reducing the dynamic range, and so, making it sound louder or whatever the 'Compression type' setting claims. The Limiting preset prevents the output from Harmless exceeding 0 dB (assuming its Mixer track and Channel setting volumes are at the defaults). When Limiting the Mix control is disabled. The remaining presets offer various compression 'flavors' as described by their names. Distortion does what it says. Set by ear.
    • Mix - Control the mix between the dry and effected signal. Right = 100% effected.

    NOTE: If the effects chain Harmless feeds into already has compression/limiting then don't use the internal effect.

CPU options

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

  • Processing quality - Select from normal where everything is normal or high quality where the sonic beauty will make you weep with desire. Use high quality mode for better live quality on transients and very fast LFO's. Quality comes at the cost of CPU load. NOTE: Harmless uses ultra high quality when rendering, and no you can't have that for live use, unless you are using the VST version then it's available on the Hint Bar Options menu.
  • threaded - Allows multi-threading for improved multi-core CPU performance. Switching threading off may, in some cases, improve performance if the host's multithreading is more efficient than the plugins own.

About Harmless (?)

  • ? - Shows the about screen. Don't press this button if your Grandmother is watching!
  • Keyboard - Open/close the preview keyboard.

Special note colors

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

  • MIDI Channel 14 - Invert legato state, mono (slide) override, use in conjunction with MIDI Channel color 1.
  • MIDI Channel 15 - Invert portamento state, use in conjunction with MIDI Channel color 1.
  • MIDI Channel 16 - Filter cutoff frequency. The absolute frequency is based on a defaulted (middle) filter freq knob setting. The note does not play on its own.

NOTE: Click on the colors OR text to select.

Plugin Credits

Code & GUI: Didier Dambrin.