By John Papiewski Updated Mar 24, 2022

The human ear can detect frequencies from 20 to 20,000 Hz. While higher frequencies are inaudible, low‑frequency sounds—known as infrasound—can be felt as vibrations. Common sources such as bass drums, explosions, and thunder produce these inaudible tones alongside audible sound. Subwoofers, designed to reproduce the lowest frequencies, add realism to audio experiences in film, gaming, and live events. By pairing a variable‑frequency sine‑wave oscillator with a self‑amplified subwoofer, you can generate infrasound for testing or creative projects.

Step 1

Power on the subwoofer and the oscillator. Set the oscillator’s output amplitude to its minimum. Tune the oscillator to 10 Hz and adjust the subwoofer’s volume knob to its lowest setting.

Step 2

Connect the BNC female connector to the oscillator’s BNC male output. Use a BNC‑to‑RCA adapter cable to link the oscillator’s RCA male plug to an RCA input on the subwoofer.

Step 3

Increase the subwoofer’s output to roughly one‑quarter to one‑half of its maximum capacity.

Step 4

Gradually raise the oscillator’s amplitude until you begin to feel the subwoofer’s vibrations. Slowly raise the frequency; as you approach 20 Hz, the sensation shifts from tactile vibrations to a low audible pitch.

Equipment Required

• Signal generator or oscillator
• Self‑amplified subwoofer
• BNC female to RCA male adapter cable

Note: Infrasound can cause discomfort or adverse effects at high intensities. Use caution and monitor levels to maintain a safe listening environment.