Design and export custom single-cycle waveforms, wavetables, and samples for synthesizers and samplers

What is the SKR4CH Waveform Designer?

The SKR4CH Waveform Designer is a free, browser-based sound design tool for creating and exporting custom single-cycle waveforms, wavetables and sustained samples for compatible synthesizers, samplers and DAWs.

You can draw a waveform on the main canvas using nodes and curve handles, build another using the Harmonics panel, blend both sources into a final Output waveform and create W.T morphs between different states of the design.

How to use the SKR4CH Waveform Designer

A typical workflow is:

1. Create a Drawn waveform on the main canvas.
2. Build a second waveform with the Harmonics controls.
3. Use Mix to combine them into the final Output waveform.
4. Optionally add W.T control elements to create a morph.
5. Preview and audition the result.
6. Save the design and export the required audio files.

Nodes, curve handles, slider thumbs and their W.T counterparts are referred to as control elements.

Drawn waveform

Use these controls to edit regular nodes and curve handles on the main canvas. The first and last nodes are fixed end nodes: they can move vertically but remain fixed horizontally.

• Left click an empty area on the main canvas to insert a node.
• Left click and drag an existing node to move it.
• Left click and drag a curve handle to shape the line between two nodes.
• Right click an interior node to delete it.
• Right click a fixed end node to reset it.
• Right click a curve handle to reset it.

Canvas controls

• Use the mouse wheel or drag either edge of the canvas scrollbar thumb to zoom. Use the left and right arrow keys or drag the scrollbar thumb to pan. Right click the scrollbar thumb to reset zoom and pan.
• Hold Shift while inserting or dragging nodes to bypass collisions with other nodes and W.T tracks. This allows nodes to move past each other and be inserted inside W.T tracks.
• Hold Ctrl and click individual nodes or drag a selection box, using the left mouse button to add nodes to the selection and the right mouse button to remove them. Release Ctrl, then left click and drag a selected node to move the group, or right click one to delete or reset its nodes. Quickly tap Ctrl three times to clear the selection. Only nodes can be added to the selection.
• Hold Alt and left click an eligible control element to create or extend a W.T track. To apply this to eligible nodes in a selection, hold Alt and left click an eligible selected node.

Harmonics waveform

The Harmonics panel builds a second waveform from 18 individually controlled harmonic partials.

• Volume controls each harmonic’s level.
• Phase shifts each harmonic within the waveform cycle.
• Shape changes each harmonic’s waveform shape and timbre.
• Modulate provides an editable amplitude curve for each harmonic. Select a harmonic and edit its curve with the same basic canvas controls used on the main canvas.

In Volume, Phase and Shape modes, left click and drag a harmonic’s slider thumb to adjust its value. Right click a regular or Start thumb to reset it.

Sliders and button borders belonging to active harmonics are lit up. Harmonics whose frequencies reach or exceed 20 kHz at the selected note are shown in red as a warning.

Wavetables

The W.T feature allows you to create morphing waveforms by adding W.T control elements to eligible regular control elements. This creates W.T tracks that you can move through using the W.T slider.

The regular control element acts as the Start at 0%, and the last W.T control element is the End at 100%. Optional middle control elements are evenly distributed between them along the morph. The waveform morphs as you move between these positions.

W.T can be used with:

• Nodes and curve handles on the main canvas.
• Nodes and curve handles in each Harmonics Modulate curve.
• Harmonic Volume and Shape slider thumbs.
• Mix slider thumbs.

Phase does not support W.T.

• Hold Alt and left click an eligible regular control element to create a W.T End control element. Repeat on the current End to add a new End; the previous End becomes a middle control element.
• Left click and drag existing Start, middle and End control elements to move them. Alt is not needed.
• Right click a W.T middle or End control element to delete it.
• On a slider that supports W.T and has only its regular thumb, left click or drag anywhere on the slider track to move the thumb, right click the track to reset it, or hold Alt and left click the track to create a W.T End. Once W.T middle or End thumbs exist, interact directly with the required thumb.
• Left click or drag the W.T slider to preview the morph from Start to End. Right click it to return to Start. The selected W.T position remains fixed during playback unless you move the slider.
• Use the D, O and H buttons to choose whether the W.T panel focuses Drawn, Output or Harmonics.

A red W.T track and disabled red curve handles warn that node order has changed during the morph.

Mixing and Output

The Mix panel blends the Drawn and Harmonics waveforms into the final Output waveform. The top of the slider is 100% Drawn, the bottom is 100% Harmonics and positions between them blend both sources.

• Left click and drag the Mix slider thumb to adjust the balance.
• Right click its regular or Start thumb to reset the balance to 50/50.

Auditioning and every export mode use Output, regardless of which waveform lines are visible or focused.

Waveform auditioning

• Click a note in the note strip to select it.
• Use the note strip arrows to shift the visible note range.
• Hold Spacebar to play Output at the selected note and current W.T position. Release it to stop.
• The physical keyboard maps left-to-right across the visible notes using 1 through =, Q through ], A through ', then Z. Hold a mapped key to play its note, or hold multiple keys to play chords. Release the keys to stop those notes.
• Changes are heard in real time while a note is playing.

Display panel

The Display panel controls which waveform lines and guides are shown on the main canvas. These controls do not change the sound or exported audio.

• Drawn, Output and Harmonics toggle their waveform lines. Drawn must be visible to edit its control elements on the main canvas.
• Highlight toggles pointer guides and applicable coordinate or curve readouts.

Grid panel

The Grid panel controls the canvas grid and node snapping.

• X and Y set the grid divisions. Setting an axis to 0 disables its divisions and snapping.
• Snap X and Snap Y snap nodes to those divisions. Curve handles remain freely adjustable.

Waveform focus

Hovering over the main canvas, Harmonics, Mix or W.T panels focuses the relevant waveform visually. Focus affects presentation and editing emphasis, not the sound, and only visible waveforms can receive focus.

Actions panel

• Help explains the main controls and how to use them.
• Save opens a menu for saving the waveform designer state as a .txt file or copying a shareable link.
• Info expands or collapses this guide.
• Load restores a valid current-version SKR4CH .txt state file.
• Settings opens the interface Scale and Volume controls.
• Reset returns the waveform designer to its defaults, except for interface Scale and Settings Volume.
• Donate opens the external SKR4CH donation page.
• Export opens the audio export options.

Saving and loading

The .txt file and shareable link preserve the same waveform design and W.T position. Temporary selections, grid divisions, display settings and other interface-only preferences are not included.

• Use Load to open a saved .txt file, or open a shareable link in your browser to load its design.
• Only current-version save files and shareable links are supported. Unsupported or invalid data is rejected without replacing the current design.
• If a design is too large for a shareable link, use the .txt option instead.
• After editing a design, copy a new shareable link to share the updated version.

SKR4CH has no waveform-editing undo/redo or autosave, so save before making changes that you may want to reverse.

Settings

• Auto Scale fits the interface to the selected percentage of the browser width. Left click or drag the Scale slider to adjust the percentage, or right click it to restore 57%. Turn Auto Scale off for 1:1 sizing.
• Volume adjusts the playback level from 0% (silent) to 100% (full level). The left readout shows decibels (−∞ at 0%); the right shows the percentage. Left click or drag the slider to adjust it, or right click to restore 100%. Volume affects playback only and does not change the waveform design or exported audio.

Exporting

All export modes export the final Output waveform as mono WAV audio. Choose an export mode, sample rate and bit depth:

• Single-cycle waveform: exports one cycle at the current W.T position using the selected sample count.
• Wavetable: exports numbered frames distributed across the complete W.T morph as separate WAV files, using the selected frame and sample counts.
• Sustained sample: exports the current W.T position at the selected note or a custom frequency for the chosen duration.

Wavetable export saves the numbered files in a folder where supported, or downloads them in SKR4CH_Wavetable.zip.

Applications

• Load single-cycle waveforms into compatible hardware or software synthesizers as oscillator sources.
• Load numbered wavetable frame sets into compatible wavetable synthesizers to create evolving timbres.
• Use sustained samples in samplers, granular tools, resynthesis workflows or directly in a DAW.

YouTube channel

https://www.youtube.com/@SKR4CH