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.
Outline AC 4 Ultra-Compact 4″ Passive Enclosure (White)
RRP: $999.00 ex. GST
Key Features:
- Ultra-compact passive speaker system with 4-inch full-range driver
- Custom Italian-engineered transducer designed exclusively for AC 4
- Single-driver design for natural, phase-coherent sound reproduction
- HCDF (Hydrophobic Compact Density Fiber) cabinet construction
- Distinctive O-ring design for vibration damping and surface protection
- Professional 16-ohm impedance optimized for distributed systems
- Impressive 118 dB SPL maximum output from compact enclosure
- 70W AES continuous power handling (280W peak)
- Frequency response: 110 Hz to 17 kHz (-10 dB)
- Axisymmetric 60-degree nominal dispersion pattern
- Multiple mounting points (2x M6, 3x M4, 1x M10 on bracket)
- Includes custom multi-adaptable mounting bracket
- Ultra-compact dimensions: 120 x 120 x 126 mm
- Lightweight design at only 1.55 kg
- Available in black or white textured polyurethane finish
- Custom RAL colour finishes available on request
- Epoxy powder-coated protective grille
- Ideal for museums, restaurants, lounges, conferences, and discrete installations
- Plug-and-play compatibility with Outline L3000 power amplifier
Technical Data
| Type: | 1-way ultra-compact passive enclosure |
| Driver: | 4″ High Power & Dispersion Full-range Driver |
| Frequency Response (-10 dB): | 110 Hz – 17 kHz |
| Nominal Dispersion: | Axisymmetric 60° |
| Impedance (Nominal/Minimum): | 16 Ω / 12.7 Ω |
| Power Handling (Continuous/Peak): | 70W / 280W AES |
| Maximum SPL Output: | 118 dB SPL |
| Cabinet Material: | HCDF (Hydrophobic Compact Density Fiber) |
| Cabinet Finish: | Black or White textured polyurethane paint |
| Grill: | Epoxy powder coated |
| Installation Points: | 2 x M6 + 3 x M4 on rear panel + 1 x M10 on bracket |
| Dimensions (H x W x D): | 120 x 120 x 126 mm (4.7″ x 4.7″ x 5″) |
| Weight: | 1.55 kg (3.4 lb) |
| Included Accessories: | Multi-adaptable mounting bracket |
| Shipping Dimensions (H x W x D): | 130 x 170 x 150 mm |
| Shipping Weight: | 2 kg |
| Country of Origin: | Italy |



