Wave Drawing Synth

In this simulation students draw one cycle of a sound wave on a grid with the pointer, and the browser loops it as a continuous tone. A frequency slider from 55 to 880 hertz sets the pitch, while presets load a sine, triangle, square or sawtooth shape to compare. Bars show how much of each harmonic the drawing contains, and readouts show the frequency, nearest note, strongest harmonic and wavelength. Sharp corners create many high harmonics and a bright sound, while smooth curves give a pure tone. It introduces timbre, harmonics and the idea that any repeating sound is a sum of sine waves.

• Draw a smooth hill and valley, then compare it with the Sine preset and listen for the difference.
• Draw a shape with sharp corners and watch the harmonic bars grow at higher numbers.
• Load Square, then Sawtooth, and compare the harmonic bars and the tone of each.
• Raise the Frequency slider and read how the nearest note and wavelength change.
• Turn Join ends off, draw a jagged wave and listen for the click, then turn it on again.

1. 1Explain that the shape of a wave determines the timbre of a sound.
2. 2Relate sharp corners in a wave to the presence of high harmonics.
3. 3Compare sine, triangle, square and sawtooth waves by sound and harmonics.
4. 4Describe how frequency sets pitch while shape sets tone color.

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