How to Make a Silent Subliminal (the Ultrasonic Layer)

Modulates a copy of each voice onto a near-ultrasonic carrier. Use the audible check to hear the encoded signal at a lower test frequency, and export WAV when this layer matters.

The silent layer amplitude-modulates a copy of each voice onto a very high carrier tone, sometimes called the Lowery method. At 18.5 kHz the carrier is above the hearing range of many adults, but some listeners may still hear a faint high tone. Stop playback or turn the layer off if it is uncomfortable.

Use the audible check (“Hear what’s hidden”) to inspect the encoded signal. It lowers the carrier to 8 kHz for preview only and is not included in the export.

This layer lives at the very top of the spectrum, so the file format matters: export lossless. Export WAV when this layer matters. MP3 compression does not reliably preserve near-ultrasonic content.