Cicada Audio FLX1400.4 — Ultra-High-Power 4-Channel Class-D Motorcycle Amplifier (1,400W RMS / 350W x4 @ 2Ω)

Power Output — What the Numbers Mean

The FLX1400.4 is rated at two supply voltages, matching real-world motorcycle conditions. At 14.4V — a fully charged, engine-running system — the amp delivers 225W × 4 at 4Ω and 350W × 4 at 2Ω. At 12.5V — closer to battery voltage under heavy load — output drops to 200W × 4 at 4Ω and 300W × 4 at 2Ω. The 2Ω figures at 14.4V drive the product name: 350W × 4 yields approximately 1,400W total RMS at rated voltage.

Bridged, the amp produces 700W × 2 at 4Ω at 14.4V (600W × 2 at 12.5V) — the configuration for maximum per-channel output to a dedicated mid-bass enclosure, subwoofer, or high-output two-channel front stage. At 4Ω bridged, the amplifier sees a 2Ω load per side — within the FLX1400.4's rated bridged impedance specification. On the road: at 50A music-level current draw, the FLX1400.4 operates within a cautious margin for most factory Harley charging systems under normal riding conditions — notably more conservative than the FLX2000.4's 60A draw or the lithium-dependent current profile of the FLX2000.4 at full rated output.

Crossover and Signal Control

The FLX1400.4 runs HPF, LPF, or Full Range crossover modes with a frequency range of 30 Hz–300 Hz and a fixed 12 dB per octave slope. This covers the primary use cases for a high-power 4-channel motorcycle amp — high-pass filtering for fairing speakers, low-pass filtering for a rear mid-bass or subwoofer channel, and full-range operation for coaxial speakers. The 12 dB/octave slope is well-matched to coaxial and mid-bass builds.

For builds requiring steeper driver-separation slopes — dedicated horn tweeters and midrange drivers where 24 or 48 dB/octave gives cleaner isolation — the FLX700.4's crossover architecture handles that role at 175W × 4. The FLX1400.4 is the choice when maximum per-channel output for coaxial and mid-bass builds is the priority. Input sensitivity runs 0.2V–12V, covering both OEM Harley signal levels and standard RCA output from aftermarket head units.

Built for the Motorcycle Environment

The circuit board is conformal coated — a protective film sealing the electronics against moisture, humidity, and vibration-borne dust — and the whole amplifier is encased in an extruded aluminium heatsink chassis. On the road: road spray, humidity swings, and constant vibration are the normal operating environment for a fairing- or bag-mounted amp, not an edge case — this is the packaging that survives them.

The ICAD overload protection circuit guards the output stage against short circuits, thermal overload, and wiring faults, and two indicators handle the diagnostics: a power/protect LED that shows blue in normal operation and red in protect mode, and a dedicated clip LED that should only flash on musical peaks. If the clip LED holds solid for more than 2–3 seconds, back the volume or gain off. On the road: gain setting and fault-finding by eye — a shorted speaker wire or an overheating amp announces itself before it becomes a failure.

The crossover and gain potentiometers are detented — they click through fixed positions rather than sweeping freely, so settings are exact, repeatable, and immune to vibration drift. On the road: the crossover point set in the workshop is still the crossover point after a corrugated highway — and a known-good tune can be replicated on a second bike click-for-click.

Power and ground run through busbar-style terminals accepting up to 4 AWG wire, with 12 AWG busbar speaker terminals that clamp solid on bare speaker wire — no crimped pins to work loose under vibration. Signal input is via Molex® connectors, hooking up through standard RCA or H-D custom-terminated harnesses, and the speaker-output side can run plug-and-play through the HDFLXFO front and HDFLXRO rear H-D speaker output harnesses.

Mounting Options

Every FLX amplifier ships with two sets of mounting brackets: standard brackets (preinstalled) for flat-surface mounting, and inverted brackets that mount the amp top-face down — keeping the cooling fan on fan-equipped models facing downward with proper airflow clearance. The brackets carry multiple mounting points and can be trimmed or modified to suit a specific fairing, amp rack, or bag install without compromising structural integrity. Where there is no surface to screw into, the included 3M® locking velcro, zip ties, or straps secure the chassis directly. For 2024+ Road Glide® and Street Glide®, the model-specific 24HDAR-RG and 24HDAR-SG single-amplifier mounting systems bolt an FLX amp into the fairing without custom fabrication. On the road: the amp adapts to the space the bike actually has — factory amp tray, amp rack, or a tight custom cavity — rather than dictating it.

System Integration

The FLX1400.4 accepts high-level speaker output from the factory Harley Boom! Box radio directly — no additional converter required for 2014–2023 models — or low-level RCA from any aftermarket head unit. Turn-on supports REM and DC offset modes. DC offset turn-on is useful on older Harley platforms where routing a clean remote wire to the factory head unit is not practical.

At 50A music-level current draw, the FLX1400.4 operates within a cautious margin for most factory Harley charging systems under normal riding conditions — but maximum draw is 220A, and the wiring infrastructure must be rated accordingly. A 120A fuse is required on the power feed. For builds pairing the FLX1400.4 with additional amplifiers or high-draw accessories, verify total system current load against the bike's alternator output and battery capacity before finalising the design. The HDPG4K 4 AWG power and ground kit is the correct wiring solution for this amplifier.

The FLX1400.4 does not include onboard DSP. For builds requiring time alignment, multi-band EQ, or advanced signal routing, pair with a dedicated DSP processor upstream of the amp inputs — or consider the FLX1400.4PRO for the same output with integrated DSP in a single chassis.

A 2ch/4ch input switch lets channels 1/2 feed all four outputs from a single stereo pair — no external Y-adapters needed when running a 2-channel source into a four-channel or bridged configuration. For bikes retaining the factory Harley amplifier, Cicada's HDFiMY or HDFiM56Y-1.5 harness handles the OEM amplifier connection.

Wiring matters at these current levels: use properly sized OFC (oxygen-free copper) power and ground wire only — never CCAW (copper-clad aluminium), which carries less current for the same gauge and heats under sustained draw — and locate the main fuse within 457 mm (18") of the battery terminal. For systems at or above 1,400W total output, Cicada strongly recommends upgrading the OEM battery to a lithium battery — not a hard requirement at this level, but the upgrade that keeps supply voltage close to the 14.4V rated condition under sustained draw.

2024+ Platform Notes

For 2023.5 CVO and 2024+ Harley-Davidson Touring models running Skyline OS, the FLX1400.4 can be integrated as part of an aftermarket audio system when paired with a NAV-TV ZEN-H or ZEN-H Pro. The ZEN-H / ZEN-H Pro handles the Skyline OS signal interface — the FLX1400.4 then receives the processed output and powers the speakers downstream from it. Without a NAV-TV ZEN-H or ZEN-H Pro, integration with a 2023.5 CVO or 2024+ Harley is not supported. For 2014–2023 models (excluding 2023.5 CVO), the high-level input connects directly to the factory Boom! Box radio.

Technical Specifications