Waveform Recognition Quiz
Train your ear to tell the basic synth waveforms apart. A tone plays at a fixed pitch as a sine, square, triangle, sawtooth, or filtered noise — your job is to name the shape from its timbre. After each guess, the actual waveform is drawn over one period and its harmonic content is explained.
ℹ This is an uncalibrated ear-training game, not a test or certificate. The sounds use the standard Web Audio oscillator types at a fixed pitch; what you hear depends on your headphones or speakers and your ears. Your score is a personal practice metric saved only in your own browser — nothing is uploaded. Use a moderate listening volume.
Press “New tone” and listen, then pick the waveform you think you heard.
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The reference pitch is fixed at 220 Hz (A3) so you judge timbre, not pitch. Tuning is 12-TET, A4 = 440 Hz.
How It Works
Every pitched sound is built from a fundamental frequency plus a stack of harmonics (whole-number multiples of it). The fundamental sets the pitch; the recipe of harmonics above it sets the timbre — the “colour” that lets you tell a flute from a violin playing the same note. This waveform recognition quiz holds the pitch fixed at 220 Hz (A3) and changes only the waveform, making it a pure waveform listening test: the only thing your ear has to judge is that harmonic recipe. If you want to see the harmonic series of a note laid out numerically, the harmonic series calculator lists every partial and its frequency.
The five sounds are generated with the standard Web Audio API oscillator waveforms and a noise source: a sine wave is a single pure frequency with no harmonics; a square wave contains only the odd harmonics at strong amplitude (a hollow, clarinet-like buzz); a triangle wave also contains only odd harmonics but they fall off much faster (at 1/n²), so it sounds soft and mellow; a sawtooth wave contains all harmonics, odd and even (falling at 1/n), and sounds bright and buzzy like a bowed string or brass instrument; and filtered noise has broadband energy spread across a wide band of frequencies at once (here roughly 200 Hz to 8 kHz), so there is no single pitch and it reads as a hiss or rush. After you answer, the tool draws one period of the chosen waveform and names its harmonic content so you can connect the sound to the shape and identify the waveform by sound more reliably next time. To compare these waveforms visually with any live input, the waveform visualizer shows the oscilloscope view in real time.
Difficulty scales in three steps. Level 1 contrasts only sine versus sawtooth — pure versus maximally bright, the easiest pair to separate. Level 2 opens up all five shapes. Level 3 weights the quiz toward the genuinely tricky pairs, especially square versus sawtooth (both buzzy, differing only in the presence of even harmonics) and the odd-harmonic siblings square and triangle (both odd-only, but with very different rolloff rates). This kind of timbre discrimination training directly transfers to real-world tasks like identifying oscillator types on a synthesizer patch, recognising an instrument in a mix, or making targeted EQ decisions. The science of the waveforms is exact, but recognising them by ear is a perceptual skill that depends on practice, your playback gear, and your hearing — so treat the score as practice feedback, not a verdict.