RCF SUB 708-AS MK3: 18" Low-End Authority for Mobile DJs & Live Sound
The SUB 708-AS MK3 is a portable, high-power active subwoofer designed to hit hard and stay clean in real-world rooms. Its 18" transducer and
1400 W Class-D amplifier deliver up to 133 dB of deep, controlled bass with Bass Motion Control excursion management. A stereo input section with
selectable crossover, high-pass outputs, EQ, and polarity reverse streamlines 2.1 rigs for DJs, bands, and corporate AV. Convection cooling keeps the amp silent,
while the rugged Baltic birch cabinet with polyurea coating, steel grille, and M20 pole mount stands up to the Chicago load-in, week after week.
Internal signal flow is optimized for fast setup: balanced stereo XLR in ? onboard processing and limiting ? switchable LINE or HIGH PASS stereo outs to your tops.
Choose crossover behavior, match polarity at the dance floor, set gain, and go. When you need more coverage, add a second unit and mirror settings.
Amp/DSP highlights include soft limiting and protection, program-friendly EQ shaping, and precise crossover options that reduce low-mid mud without
thinning vocals. With 35 Hz–120 Hz bandwidth and intelligent excursion control, the MK3 platform keeps kick, 808s, and bass guitar tight and musical.
- Real-World Applications and Sound Roles: Mobile DJ mains support • Live drums + bass reinforcement • Small club installs • Corporate AV 2.1 systems • Ceremony + reception changeovers
Where the RCF SUB 708-AS MK3 Excels
- Mobile DJ Impact: 18" driver + 1400 W peak keeps kick and 808s present without blowing up vocals.
- Fast 2.1 Wiring: Stereo XLR in/out with selectable LINE or HIGH PASS speeds setups and changeovers.
- Room-Friendly Control: Polarity reverse and EQ help you fix cancellations and tame hot rooms quickly.
- All-Night Reliability: Convection cooling (no fan) and soft limiter protections maintain consistent output.
- Tight Low-End: Bass Motion Control limits only over-excursions for deeper, cleaner bass at show levels.
- Right-Sized Pairings: Optimized with 8" or 10" tops; scale with a second sub for wider rooms.
- Road-Strong Build: Baltic birch, polyurea coating, steel grille, and ergonomic handles handle daily transport.
Control Modes for RCF SUB 708-AS MK3
- Inputs/Outputs: Stereo XLR inputs; stereo XLR outputs selectable as LINE (full-range thru) or HIGH PASS to feed satellites.
- Crossover: Switchable crossover behavior for clean 2.1 integration; LOW-PASS to sub at 80 Hz, and HIGH-PASS out option including 110 Hz to lighten compact tops.
- Polarity Reverse: Flip phase to maximize summation with mains at the crowd position.
- EQ & Volume: Onboard gain and program-friendly EQ for tonal balance and level matching.
- Input Sensitivity: -2 dBu / +4 dBu selection for mixer compatibility.
- Protections: Electronic equalization, soft limiter, thermal and RMS safeguards.
Power That Moves the Room
A 1400 W peak / 700 W RMS Class-D module delivers fast transient attack with low heat loss. The silent, fan-free design uses a solid aluminum heat
exchanger for dependable performance during long receptions and club nights.
Bass Motion Control Explained
BMC maps the woofer’s dynamic behavior and limits only over-excursions, preserving phase integrity and extending low-frequency linearity.
Result: deeper bass that stays tight as the dance floor fills.
Tour-Ready Construction
The Baltic birch enclosure with polyurea coating and powder-coated steel grille resists daily transport wear. Ergonomic side handles ease load-ins,
and the top M20 threaded mount secures your satellite loudspeakers.
Stereo Crossover Workflow
Route mixer L/R to the sub, then choose HIGH PASS outs to your mains to clean up low-mid overlap. Start with 80 Hz low-pass to the sub and
evaluate a 110 Hz high-pass to the tops when using compact 8"–10" speakers.
How to Deploy the RCF SUB 708-AS MK3 in the Field
Place the sub slightly forward of the mains to reduce boundary cancellations. For wider rooms, use a pair spaced symmetrically. Keep cable runs tidy and
short; verify polarity where the audience stands, not just at FOH.
- Stacking & Mounting: Use the M20 pole mount for satellites; ensure level footing before raising poles.
- 2.1 Routing: Mixer L/R ? sub inputs; sub outputs set to HIGH PASS ? satellites.
- Starting Points: Low-pass to sub at 80 Hz; try 110 Hz high-pass on tops with compact mains.
- Polarity Check: Flip polarity and choose the setting with strongest bass at the dance floor.
- Scaling Up: Add a second sub for smoother coverage; mirror controls and spacing.
Tune at the audience position—set crossover, then polarity, then gain. Lock it in and keep sets moving.
Why Choose the RCF SUB 708-AS MK3 from AVMaxx
AVMaxx supports Chicago DJs, bands, and event pros with build-tested deployment tips and bundled pairings tailored to tight turnarounds and mixed-use venues.
From crossover selection to polarity checks, we help you extract consistent, musical low-end from day one.
AVMaxx is your partner for field-aware recommendations and confident, show-ready rigs—built around how Chicago events actually run.
Frequently Asked Questions — RCF SUB 708-AS MK3
What frequency range and output can I expect?
Frequency response is 35 Hz – 120 Hz with a maximum SPL of 133 dB at 1 m. The 1400 W peak / 700 W RMS amplifier provides ample headroom for live and DJ use.
Which crossover settings work best with compact tops?
Start with a sub low-pass around 80 Hz and use the sub’s HIGH PASS outputs to feed your satellites. A 110 Hz high-pass helps lighten 8"–10" tops.
What do the rear-panel controls include?
Stereo XLR in/out (LINE or HIGH PASS), volume, EQ, polarity reverse, crossover selection, and input sensitivity of -2 dBu / +4 dBu.
Is there a fan in the amplifier?
No. It uses convection cooling with a solid aluminum heat exchanger for quiet, reliable operation.
DJ use: will one unit cover a typical wedding or small club?
Yes for most small to mid-sized rooms; add a second unit for wider coverage or higher headroom on bass-heavy sets.
What are the size and weight?
693 × 505 × 685 mm (27.28 × 19.88 × 26.97 inches); 40.6 kg (89.51 lb). Top M20 pole mount for satellites.
