Let’s rewind the tape. The Subliminal Recording System 80 (often abbreviated as SRS-80) was not a single piece of hardware but rather a methodology and a suite of hardware popularized in the early 1980s. Unlike today’s MP3 downloads, the SRS-80 relied on the physical limitations (and advantages) of analog magnetic tape.
At its core, the system used a dual-layer audio recording technique. On the surface, a user would hear a "masking track"—usually pink noise, ocean waves, or relaxing piano music. However, buried roughly 6 to 10 decibels below the audible threshold was the "subliminal track." subliminal recording system 80
That technology was the .