Technology on Instagram: "A company in Brazil has turned pickup trucks into full blown mobile concert systems. Evok Áudio builds paredão setups with walls of mid and high frequency speakers up front and subwoofers filling the truck bed for massive bass. A digital signal processor manages the audio by splitting frequencies, aligning timing, and shaping the sound for clarity over volume. Class D amplifiers draw power from lithium battery banks and high-output alternators, with thick copper wiring