Filters

Passing lows, blocking highs

An interactive lesson with 7 steps, about 6 minutes: you predict, drag and solve, with instant feedback on every answer. It runs in your browser and needs JavaScript.

What you’ll learn

• Capacitor reactance $X_C = 1/(2\pi f C)$: high for low frequencies.
• An RC low-pass filter has cutoff $f_c = 1/(2\pi RC)$.
• Filters split sound between speakers and shape tone.

Steps

1. Capacitors and AC
2. A low-pass filter
3. Sweeping the pitch
4. Find the cutoff
5. Block the rumble
6. Ten times the cutoff
7. At the cutoff