The unique bass restoration circuit of The Epicenter®, originally patented by AudioControl, looks at the upper harmonics and uses them to digitally recreate low frequency fundamentals (original frequency) that have been lost through compression (MP3s), rolled-off, or simply removed (during mastering). The Epicenter® digital restoration occurs from 27 Hz to 63 Hz and may be parametrically shaped using the Wide and Sweep knobs on The Epicenter Concert Series and The Epicenter InDash. The chart below shows how The Epicenter®, by analyzing the upper harmonic frequencies, restores the bass, which was previously non-existent in some music you listen to.
Epicenter product pages here