Audio lab · Beamforming

Microphone array beamforming simulator

Beamforming combines the signals of several microphones so that sound from one direction adds up in phase and sound from other directions partly cancels. This simulator steers an ideal delay-and-sum linear array toward one of two tones and plots its directional response, so you can see and hear how the steering angle and the number of microphones change what gets through.

SYNTHETIC SIGNALS

These demos are illustrative. Every signal is synthetic, generated and processed in your browser, and every number shown is computed from those signals. They show the principles, not the measured performance of a product.

Press a listen button to play a short sample. Sound starts only when you press a button. No microphone or uploads needed.

Spatial acoustics

Point the listening beam.

Two tones arrive from different directions. Steer a virtual microphone array toward the sound you want.

Control the array

Listening direction

Number of microphones

Microphone spacing: 4 cm. More microphones increase the aperture and sharpen directional selectivity.

A / −35°1,000 Hz tone

B / +45°650 Hz tone

Directional sensitivity

0° = broadside

Blue: response at 1,000 HzAmber: response at 650 Hz

Source A gain—

Source B gain—

Array aperture—

0 dB means fully retained; negative values mean attenuation. Directional response depends on frequency. Both sources can remain audible.

Where this matters

Microphone arrays, directional sensing and audio capture on devices. Geometry, frequency, reverberation and compute budgets shape real-world performance.

What this experiment models

An ideal uniform linear delay-and-sum array in the far field, with sound speed 343 m/s and equal source amplitudes. The chart uses the normalized complex array factor. Playback applies that factor’s gain and phase to each synthetic tone. It models two steady tones, not speech, moving sources, reverberation, microphone mismatch or an actual hardware recording.

The principle

How it works

A source off to the side reaches each microphone at a slightly different time. A delay-and-sum beamformer delays each channel to undo that arrival-time difference for the chosen look direction, then averages the channels. Sound from the look direction adds coherently; sound from other directions arrives with mismatched phases and is attenuated by the amount the array factor in the chart shows.

The microphones here are 4 cm apart. Adding microphones widens the aperture, which narrows the main lobe and deepens the attenuation away from it. The response also depends on frequency: the two sources are tones at 1,000 Hz and 650 Hz, and the lower tone sees a wider beam from the same array. Side lobes mean an off-axis source can still leak through at some angles.

Real arrays add reverberation, microphone mismatch, moving talkers and a compute budget, which is where adaptive beamformers and learned spatial filters come in. See microphone arrays and beamforming.

Audio lab

More demos

01 / Noise filteringLow-pass filter noise reduction – interactive demoLow-pass filtering, input and output SNR 03 / Active noise controlActive noise control (ANC) interactive demoCancel a hum with an opposing tone 04 / Bearing fault vibrationBearing fault vibration analysis – interactive demoEnvelope analysis finds an outer-race defect 05 / Sound event detectionSound event detection – interactive demoHits and false alarms of an energy detector 06 / Speech enhancementSpectral subtraction speech enhancement demoSpectral subtraction and musical noise

All six demos on one page: the audio lab Microphone arrays and beamforming →

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