Audacity is not a game audio engine, and it is not a synthesizer in the modular sense. It is an editor with a small set of generators and a deep set of destructive and non-destructive processors. That combination is enough to build a platformer jump from nothing, but the workflow is different from a generator that is designed around parameter curves.
The most common first attempt is to use the Chirp generator with a square wave and an upward sweep, then normalize the result. That produces a sound that is recognizably a jump in isolation and fails in the game, because the attack is too soft, the tail clicks, and the pitch bend is either linear in a way that sounds wrong or missing entirely. The sections below work through the three decisions that separate a working jump from a first attempt: how to generate the sweep, how to shape the envelope without clicks, and how to export it so the engine accepts it without resampling.
The Fastest Route: Chirp With a Square Wave and a Logarithmic Sweep
Audacity’s Chirp generator is the closest thing it has to a dedicated jump tool. It generates a tone that sweeps between two frequencies and two amplitudes, and it exposes the waveform, the sweep type, the start and end frequency, and the duration . The documented jump recipe in Audacity is direct: Generate → Chirp, set the waveform to Sine or Square, set the start frequency low (for example 150 Hz) and the end frequency higher (for example 600 Hz), and set the duration between 0.15 and 0.25 seconds .
The sweep type is the parameter that most first attempts get wrong. Chirp offers Linear and Logarithmic interpolation, and the documentation is explicit that logarithmic is the right choice for a sweep that sounds like it is rising evenly, because pitch is perceived logarithmically. Linear spends most of its time in the top of the range and is better suited to measurement than to a musical or game sweep .
The waveform choice matters for the game’s aesthetic, not for the sweep itself. A square wave has a hollow, digital character that cuts through a mix; a sine wave is smoother and more neutral. Audacity’s Chirp also offers a Square (no alias) option, which avoids aliasing distortion at the cost of slower generation . For a retro platformer, the aliased square is often the right character; for a cleaner sound, the no-alias version is safer.
When Chirp Is Not Enough: Time Track and the Sliding Pitch Shift
Chirp generates a sweep as a single operation, but it cannot create a bend that starts at a fixed pitch, rises, and then returns, or a sweep whose rate changes partway through. Those shapes require a different tool.
Audacity’s Time Track is the native way to create a continuous pitch bend. It dynamically alters playback speed across the project, which simultaneously modulates pitch. The documented pitch-bend setup is to add a Time Track, set its range so the lower speed is 50% (half speed, down an octave) and the upper speed is 150% or 200% (up an octave or more), then use the Envelope Tool to place control points at 100% and drag the bend point up or down . A subsequent point back at 100% returns the track smoothly to its original pitch and tempo.
The Time Track affects all tracks playing simultaneously, so it is not a per-clip processor. If the bend is only supposed to apply to the jump, the jump has to be on an isolated track or the other tracks have to be muted. The documentation notes that the effect can be rendered permanently with Tracks → Mix → Mix and Render, or left as a real-time modulation until export .
The alternative is Sliding Time Scale / Pitch Shift , which applies a continuous change to tempo and/or pitch over a selection by specifying initial and final values. It is more surgical than the Time Track because it operates on the selection rather than the whole project, but it is also a destructive effect that has to be applied before the envelope is shaped. The square wave and pitch sweep guide covers the synthesis side of the sweep; Audacity’s contribution is that the sweep can be generated or modulated after the fact, not only synthesized from scratch.
The Envelope: Why the Default Fade-Out Clicks, and What to Use Instead
A jump that ends abruptly at a non-zero amplitude produces a click. The standard fix in Audacity is a fade-out, but the default Fade Out effect is linear, and a linear fade on a short transient often sounds like the sound is being cut rather than decaying.
The documented jump workflow in Audacity says to apply the Envelope Tool to fade the tail out quickly to prevent a clicking artifact . The Envelope Tool produces exponential fades by default, which closely model the way sounds naturally decay, and the fades are non-destructive — they can be adjusted after the fact without re-applying an effect .
The practical envelope for a jump has three points, not two. The first point is at full volume at the onset. The second is a short hold — roughly the length of the pitch sweep — at or near full volume. The third is the decay point, dragged down toward silence. The Envelope Tool’s exponential curve handles the decay between the second and third points, and because the curve approaches zero asymptotically, the tail does not produce a click.
The Adjustable Fade effect is the alternative when a more precise curve is needed. It has presets for exponential fade-out that are similar to the Envelope Tool, and it allows the fade to be shaped with a mid-fade adjustment value . The important caveat is documented: if an envelope is already present and Adjustable Fade is applied, there is a known bug where the envelope is removed and the audio reverts to full amplitude before the fade is applied . The safe order is to apply Adjustable Fade first, then draw the envelope, or to use the Envelope Tool exclusively and avoid the effect.
There is a second, more important caveat that applies to any pitch-shifting effect. The Change Pitch effect has the same documented bug: if an envelope is present when the effect is applied, the envelope is removed and the audio reverts to full amplitude . This means the workflow order matters. If the pitch bend is applied after the envelope is drawn, the envelope will be lost. The safe sequence is: generate the tone, apply any pitch shifting, then draw the envelope last.
The Attack: Why a Normalize After Chirp Is Not Enough
A Chirp-generated tone starts at full amplitude by default, because the start amplitude is set to 0.8 and the end amplitude to 0.1 in the generator’s defaults . A jump needs an attack that is fast enough to read as immediate but not a hard discontinuity. Normalizing the file does not create an attack; it only changes the overall level.
The fix is a very short fade-in drawn with the Envelope Tool or applied with Adjustable Fade. A 1–5 ms fade-in is enough to remove the discontinuity without softening the transient. The Envelope Tool is the better choice because it is non-destructive and can be adjusted after listening; the Adjustable Fade effect is faster if the exact curve is already known.
A working envelope for a jump therefore has four segments, not three: a 1–5 ms fade-in from near-zero, a short hold at full volume, a pitch sweep that runs during the hold, and an exponential decay to near-zero. The fade-in is the part that most first attempts omit, and it is the part that removes the click at the start.
Export Settings: 44.1 kHz, 16-bit PCM, Mono
Audacity’s WAV export defaults are already close to what a game engine expects. The documentation states that the default sample rate is 44100 Hz, which is CD quality, and the default encoding is Signed 16-bit PCM, also CD quality . The channel options are Mono, Stereo, and Custom mapping .
For a jump sound, the correct choices are Mono, 44100 Hz, and Signed 16-bit PCM. A jump is a player-centred event, so stereo adds file size and voice cost without adding information. The sample rate should match the project rate and the engine’s expected rate; if the engine runs at 48 kHz, exporting at 44.1 kHz introduces a resampling step that can change the transient. The sample rate and format guide covers the platform-specific choices; the Audacity-specific point is that the export dialog defaults are a starting point, not a universal setting.
The project rate itself should be set before generating the Chirp, not after. A Chirp generated at 44.1 kHz and then exported at 48 kHz is resampled, and the pitch sweep’s end frequency will be slightly different in the exported file. The documented game-audio workflow recommends setting the project sample rate to 44,100 Hz or 48,000 Hz before generating anything, for standard game engine compatibility .
A Working Audacity Workflow, in Order
The sequence below is ordered so that the destructive effects happen before the non-destructive envelope, and the export happens after both. Each step corresponds to one of the decisions above.
| Step | Action | Why this order |
|---|---|---|
| 1 | Set project rate to 44.1 or 48 kHz | The Chirp is generated at this rate; changing it later resamples the file |
| 2 | Generate → Chirp: Square, Logarithmic, 150 → 600 Hz, 0.15–0.25 s | Logarithmic sounds like an even rise; square gives the retro character |
| 3 | Apply any Change Pitch or Sliding Pitch Shift now | Change Pitch removes an existing envelope, so it must happen before the envelope is drawn |
| 4 | Draw the envelope: 1–5 ms fade-in, short hold, exponential decay | The Envelope Tool is non-destructive and produces the exponential decay that avoids clicks |
| 5 | Export as WAV: Mono, 44100 Hz, Signed 16-bit PCM | Matches the project rate and the engine’s expected format; mono avoids unnecessary voice cost |
The workflow is not the only way to build a jump in Audacity, but it is the order that avoids the two documented failure modes: the envelope being removed by a pitch effect, and the click at the start and end of a short sound. The Audacity game sound effects guide covers the broader toolset; the jump-specific addition is that the order of operations matters more than the individual settings.