How does a smart speaker hear "Hey Google" from across a noisy room? It has several microphones, and it combines them cleverly to listen in one direction — toward you — while ignoring the TV and the dishwasher. Let's aim that invisible listening "beam."
🎙️🎙️🎙️ at the bottom is the mic array. Drag the 🗣️ speaker and the 📢 noise around the room. Then steer the beam to point at the speaker (and away from the noise). The clarity meter shows how well the array hears the voice!
steer the listening beam (left ↔ right)
You steered a beam by hand with delay-and-sum — the classic idea. Its beam is a bit wide, so some noise leaks in. Real devices go further:
✅ Simple, works. ⚠️ Wide beam — leaks in nearby noise; you aim it manually.
Auto-steers to the speaker AND creates a "null" (deaf spot) pointed right at the noise. ✅ Much sharper. Used in smart speakers. ⚠️ Heavier math.
A model figures out the best way to combine the mics in tough, echoey rooms. ✅ Best in hard cases. ⚠️ Needs training + more compute.
You used beamforming with a microphone array — steering a listening beam to grab a voice and ignore noise. It's how smart speakers and modern phones hear you clearly.