Guitar legends from Santana to the Beatles have incorporated the rotary speaker into their music. BOSS kept this in mind when creating the RT-20, and by employing their COSM modeling technology, it reproduces classic rotary sounds just like the originals. Adjustable Rise Time, Horn and Bass speed, Overdrive, and more. Not just for the classic swirl, the RT-20 can create unique overdrive and pulsating effects as well. Amazing sound plus a stunning graphical view of the virtual rotors in its display.