Interested in creating your own custom earcons for your app? This guide will help you create and introduce custom earcons with Android sound design best practices.
Every earcon should be:
- Immediate & Legible: Instantly distinguishable from background environmental noise.
- Acoustically Polite: Harmonious with everyday life, avoiding startle reflexes or ear fatigue.
- DSP-Aware: Thoughtfully structured to prevent distortion when processed by onboard hardware amplifiers and limiters.
Ergonomics
Ear fatigue is the primary failure mode of wearable audio. What sounds subtle on studio monitors can become irritating after 50 daily repetitions near the ear.
Apply a smooth high-shelf filter to roll off frequencies above 8 kHz. Sharp near-ear transients cause rapid listener fatigue.
Provide softened, filtered alternate assets for high-frequency interactions. For example, volume.
If an earcon triggers repeatedly within a narrow window, consider suppressing secondary triggers or transition to a minimal click, like continuous paging.
Audio file support
When delivering audio files, lean and efficient assets work best. Here are some parameters to achieve a quality audio asset.
| Parameter | Specification |
|---|---|
| Format | .ogg (Ogg Vorbis) |
| Bit Depth & Sample Rate | 16-bit / 48 kHz (or 44.1 kHz) |
| Asset Size Limit | < 1 MB (Uncompressed) |
| Headroom Ceilings | -3.0 dB to -6.0 dB True Peak |
| Channel Format | Stereo / Binaural / Mono |
Mental models
Because there are no visual indicators, users rely entirely on auditory intuition to construct mental models of the operating system. The user should feel that the obvious answer is the right one. Use the existing mental model understanding to develop a language that the user will immediately recognize. Ascending pitch trajectories are often associated with positivity. Think of a happy major scale upward, these sounds can be paired with positive interactions to enforce such mental models.
Similarly, a descending trajectory evokes finality, which can pair with negative, decreasing, or dismissal actions.
While pitch trajectories are powerful, you should use caution when solely relying on them when conveying critical state changes as they can be lost in a noisy environment. Instead pitch motion and rhythmic patterning can be used. For example, success can be conveyed with two rapid ascending chimes or a warning can use a staccato descending pulse. Ensure related actions share sound language consistency.
Spectral design
To ensure clear communication in diverse auditory environments without causing cognitive overload or physical discomfort, we recommend aligning earcon frequency distribution across three primary spectral bands:
| Spectral Region | Frequency Range |
|---|---|
| Gentle High-Pass Filtering | < 100 Hz |
| Target Audibility Band | 2 kHz – 5 kHz |
| High-Shelf Roll-Off | > 8 kHz |
Concentrate the core melodic and transient energy in the target audibility band. The human ear exhibits peak sensitivity here, allowing cues to remain distinctly intelligible without raising the master volume.
Use crisp attack envelopes so cues register instantly through background chatter, traffic, or media playback.
Use synthetic, intentional waveforms (sine, clean FM, crystalline bells) rather than naturalistic or organic samples (wood, paper, snaps). Organic textures blend into real-world ambient sounds and create confusion.
Onboard DSP adds saturation during playback. Starting with clean, pure fundamentals (sine waves or low-order harmonics) ensures clean, pristine output on physical hardware.
Duration targets
Because the glasses are being used in everyday scenarios, it's important to keep the environment clean and avoid noise fatigue. Interactions need to be thought through with the background of ambient sound from the outside environment.
| Category | Target Duration | Example |
|---|---|---|
| Micro-Interactions | 15 ms—60 ms | Short, crisp interactions. |
| Confirmations | 80 ms—220 ms | Slightly longer, with a clear beginning and end. |
| State Alerts | 250 ms—500 ms | Longer, with a clear beginning and end. |
| Hero Moments | 500 ms — 1000 ms | Longer, with a clear beginning and end. |