RCF SUB 708AS MK3 | 18in - 133 dB | Compact High-Power Active Subwoofer

High-Output 18" Powered Subwoofer for DJs and Live Sound

The RCF SUB 708-AS MK3 is a portable, high-power 18" active subwoofer designed for live performances, DJs, and small to mid-sized venues. With 1400W of Class-D amplification, Bass Motion Control technology, and up to 133 dB max SPL, this rugged subwoofer delivers tight, controlled low-end with exceptional clarity and headroom.

RCF SUB 708-AS MK3 Competitive Differences

• High-output 18" woofer with 3" voice coil and bass reflex cabinet
• 1400W Class-D amplifier with convection cooling—no fan required
• Up to 133 dB SPL output with extended low-end response down to 35 Hz
• Advanced Bass Motion Control (BMC) for improved excursion management and phase response
• Selectable crossover frequencies (80Hz / 120Hz) and polarity reverse switch
• Rugged Baltic birch cabinet with polyurea coating for touring use
• Rear panel DSP with volume, EQ, phase, and crossover controls
• Ideal companion for 8" and 10" top speakers in portable PA setups

RCF SUB 708-AS MK3 Description

The RCF SUB 708-AS MK3 is engineered to deliver professional low-frequency reinforcement in portable or installed sound systems. Its powerful 18” woofer is driven by a state-of-the-art ceramic magnet structure, delivering tight, punchy bass in a lightweight, compact format. With 1400W peak (700W RMS) power output and a frequency range from 35 Hz to 120 Hz, this subwoofer excels in music playback and live sound applications. RCF's innovative Bass Motion Control (BMC) replaces traditional high-pass filtering with a custom algorithm that maximizes low-frequency performance while preserving phase integrity. The result is a deeper, more accurate bass response with improved woofer stability and reduced distortion. Built for real-world use, the cabinet is made of Baltic birch plywood with a scratch-resistant polyurea finish. Ergonomic handles and an M20 pole mount make it easy to transport and integrate into any PA system. The rear panel includes comprehensive controls for crossover point selection, polarity, and EQ tailoring—giving users precise control over system tuning.

SUB 708-AS MK3 Features

• 1400 Watt Class-D amplifier (700W RMS)
• 18” woofer with 3” voice coil in bass reflex housing
• Bass Motion Control excursion management for extended low-end clarity
• Stereo XLR input and output with selectable high-pass output
• Switchable crossover frequencies: 80Hz / 120Hz
• Polarity reverse switch
• Rear panel volume, EQ, polarity, and crossover controls
• Soft limiter and thermal/RMS protection circuitry
• Energy-efficient convection cooling design (fanless)
• M20 threaded pole mount

SUB 708-AS MK3 Specifications

• Frequency Response: 35 Hz – 120 Hz
• Max SPL @ 1m: 133 dB
• Woofer: 18” with 3.0” voice coil
• Amplifier Power: 1400 W Peak / 700 W RMS
• Input Connectors: Stereo XLR (balanced/unbalanced)
• Output Connectors: Stereo XLR (line / high pass)
• Input Sensitivity: -2 dBu / +4 dBu
• Cooling: Convection (fanless)
• Cabinet Material: Baltic birch plywood
• Grille: Steel with acoustic fabric backing
• Handles: Two (one on each side)
• Mounting: M20 threaded pole mount
• Color: Black
• Product Dimensions (H x W x D): 27.28 x 19.88 x 26.97 in (693 x 505 x 685 mm)
• Product Weight: 89.51 lbs (40.6 kg)
• Shipping Dimensions (H x W x D): 28.94 x 22.24 x 29.33 in (735 x 565 x 745 mm)
• Shipping Weight: 100.53 lbs (45.6 kg)