Sound effects last 0.1–2 seconds. During that time, they must confirm the player's action, convey the physical properties of the object, and not become annoying after the hundredth repetition. This is especially acute in mobile games, where players perform hundreds of similar actions per session—every step, every hit, every UI click must sound natural and not irritate. We have been working on sound design for mobile games for over 5 years and know how to achieve this under strict memory and CPU constraints.
Why a single file per event is a mistake
If a step on a wooden floor is one WAV file, the brain notices the repetition after 8–10 steps. This is the "machine gun effect"—a term from game audio. The solution is a pool of variations: 4–6 variants of the same sound with small differences in pitch (±2 semitones), volume (±2 dB), and timing. In Unity, this is AudioSource.pitch = Random.Range(0.95f, 1.05f). In Wwise, a Random Container in shuffle mode.
The second level of variation is contextual variants: a step on metal sounds different than on stone. This requires a surface detection system: a raycast under the character returns the PhysicsMaterial, which selects the appropriate pool. Such architecture increases production time by 1.5–2 times, but completely eliminates monotony.
How sound effects are created for mobile games
Synthesis. For UI sounds, sci-fi effects, magic—synthesizers (Serum, Vital) and FM synthesis (FM8, DX7 emulation). An explosion in an arcade game is layering: low-end boom (sub via sine or pitchdown), transient (white noise through band-pass), tail (reverberation with decay 0.8–1.2 s). All three layers are synthesized or processed independently, then mixed. Synthesized sounds are 2–3 times cheaper to produce than Foley, but require careful tuning to sound organic.
Foley. Organic sounds—footsteps, impacts, creaks—are often recorded in a studio. A fist punch in an RPG: a real punch on a leather bag + a thin wooden crack + a synthetic transient in the high-mid (2–4 kHz for "bite"). Layering in a DAW (Reaper, Pro Tools, Nuendo), processing: EQ for body shaping, compression with fast attack to emphasize the transient, saturation for density. Foley gives a unique sound that cannot be exactly replicated by synthesis.
Libraries. Sonniss GDC Bundle (free, thousands of sounds), Boom Library, A Sound Effect—source material that is refined for the project. Taking "out of the box" without processing is bad practice: the sound will be recognizable (heard in 20 other games) and won't fit the overall palette. We refine each source—change pitch, cut, apply effects.
What are the technical requirements for sound on mobile platforms?
Final files: WAV, 44.1 kHz, 16-bit for most effects. Music stings and ambience—48 kHz / 24-bit. Stereo only for effects that will be used in 3D positioning or as music loops. Short UI sounds—mono, this halves memory.
Unity transcodes WAV to Vorbis (Android) and AAC (iOS) during build. For very short sounds (<200 ms), use Decompress On Load + PCM, otherwise decompression adds latency. For long ambient tracks—Compressed In Memory.
| Format | Setting | When to use |
|---|---|---|
| WAV | 44.1 kHz, 16-bit, mono | Most SFX (footsteps, impacts, UI) |
| WAV | 48 kHz, 24-bit, stereo | Ambient, music stings |
| PCM | Decompress On Load | Ultra-short (<200 ms) |
| Vorbis/AAC | Compressed In Memory | Long backgrounds, looped tracks |
Normalization to -16 LUFS (integrated) is mandatory before delivery. Peak limit— -1 dBTP. Without this, the mix on the device becomes uncontrollable. Compare: unprocessed sounds can differ in volume by 6–10 dB, ruining the game balance.
What is included in an SFX delivery?
All SFX as named WAV files with descriptions in the specification. If the project uses Wwise or FMOD—additionally configured events with variations inside the middleware. If Unity—prefab AudioClip with import settings or AudioMixer group. We also provide:
- a full checklist of used sources (libraries, recordings, synthesis);
- documentation on the variation system and contextual selection;
- a guarantee to replace any sound without additional charge within two weeks after delivery.
Approximate timelines
A standard set of 30–80 effects takes 1 to 2 weeks. The budget is determined individually after analyzing the game's sound map—contact us for an estimate.
To order sound effects for your game, contact us—we will evaluate your sound map and offer the best option. Request a demo set of varied SFX—we'll demonstrate quality on your scenes.