Vitalizer

The patented Vitalizer circuitry makes the Mk2-T an unsurpassed sound designer. Whether live or in the studio, audio productions sound more alive, have more details, more transparency, a higher perceived loudness and, if required, an overwhelming bass foundation.

https://www.soundonsound.com/reviews/spl-vitalizer-mk2-t

https://spl.audio/en/spl-produkt/stereo-vitalizer-mk2/