Built-in modes are repetitive loops. Audio files can be pre-programmed with 30-minute crescendos, sudden drop-offs, or patterns that mimic sexual rhythms (thrusting, pulsing, stroking). You cannot manually twist the knob fast enough to replicate a good audio track.
The 2B does not pass raw audio to your electrodes. It analyzes the incoming audio signal (from a phone, PC, microphone, or MP3 player) and converts it into its internal stimulation waveforms. estim 2b audio files
Why go through the hassle of finding audio files when you have 30 built-in modes? Built-in modes are repetitive loops