The Outline AC 4 (also known as Charlie 4) redefines what's possible from an ultra-compact loudspeaker, delivering rich, natural audio with exceptional intelligibility from a palm-sized package measuring just 120mm cubed and weighing only 1.55kg. At its heart lies a custom 4-inch full-range driver, exclusively designed by Outline's Italian engineers to deliver professional-grade performance. Moreover, the single-driver design eliminates crossover-induced phase issues, producing natural and uncoloured sound, while the innovative membrane design dramatically improves off-axis performance for consistent audio throughout the listening area. Built specifically for professional power amplifiers, the AC 4 delivers an impressive 118 dB SPL maximum output and handles 70W continuous (280W peak) with ease, making it ideal for distributed audio systems with its 16-ohm impedance. Furthermore, the HCDF (Hydrophobic Compact Density Fiber) cabinet construction ensures reliable operation even in challenging conditions, while distinctive O-rings provide vibration damping and surface protection. Additionally, every unit includes a custom-designed mounting bracket with multiple mounting points (2x M6, 3x M4, 1x M10), allowing secure installation on virtually any surface. Available in black or white textured finish with custom RAL colours on request, the AC 4 is perfect for museums, restaurants, lounges, conferences, and discrete installations where exceptional audio quality cannot be compromised, offering plug-and-play compatibility with Outline's L3000 power amplifier or any professional amplifier in your existing setup.