Cicada Audio FLX1400.4 — Ultra-High-Power 4-Channel Class-D Motorcycle Amplifier (1,400W RMS / 350W x4 @ 2Ω)
| Channels | 4 Channel |
| Power | 4x350W RMS |
| Year Range | 1998-2013, 2014-2023, 2024+ |
350W × 4 Class-D amplifier for Harley-Davidson Touring — the highest-output compact FLX amp without a lithium battery requirement
The Cicada Audio FLX1400.4 is a high-output 4-channel Class-D amplifier built for Harley-Davidson Touring — delivering 350W × 4 RMS at 2Ω and 700W × 2 RMS bridged at 4Ω. The highest-output amp in the FLX compact range to fit a standard fairing amp tray without chassis modification. Requires 4 AWG power wiring and a high-current capable supply.
There is a point in a high-output motorcycle audio build where the amplifier stops being the bottleneck and the electrical infrastructure becomes the real constraint. The FLX1400.4 sits at that line — 350W per channel from the same compact chassis profile that fits standard Harley Touring fairing amp trays, with the current demand that comes with it. For builds where the FLX1000.4's headroom is the ceiling and the system is ready for the next step, the FLX1400.4 is the answer — but it requires 4 AWG power and ground wiring from the supply to the amp, and a charging system capable of sustaining the load.
Who This Is For
For riders building a maximum-output system around high-sensitivity pro-audio drivers — and who have already committed to the electrical infrastructure the amp requires. The FLX1400.4 is the step up from the FLX1000.4 for builds where 254W per channel is no longer enough, and the step down from the FLX2000.4 for builds that don't need 542W per channel or a full lithium battery upgrade. For the same output with integrated DSP, Bluetooth streaming, and iOS App tuning, the FLX1400.4PRO is the single-chassis alternative.
What This Is Best For
- Maximum-output coaxial builds on Street Glide® or Road Glide® — 350W per channel drives the most demanding pro-audio coaxials at sustained highway volume with genuine headroom beyond the system's acoustic limits. For builds where the FLX1000.4 has already been pushed and found wanting.
- Bridged front or rear stage at 700W × 2 — 700W × 2 at 4Ω bridged delivers real authority to a dedicated mid-bass enclosure, compact subwoofer, or high-output two-channel stage. More bridged headroom than any other amp in the FLX compact range.
- Full four-channel pro-audio systems requiring maximum headroom — HPF on the front stage and LPF on the rear stage at 350W per channel means the system never approaches the clean output ceiling, even in demanding riding conditions.
- Dual-amp builds where total output is the design goal — paired with the HDPG2KD dual-amp wiring kit, the FLX1400.4 can be run alongside a second amplifier on a properly fused and wired supply circuit.
- Builds prepared for the electrical infrastructure — riders who have already upgraded to a high-current supply, run 4 AWG power and ground wiring, and confirmed their charging system can sustain the load at music-level draw.
4 AWG Wiring Required
The FLX1400.4 requires 4 AWG power and ground wiring from the supply to the amplifier. Standard motorcycle audio installs using 8 AWG wiring are not adequate for this amplifier at rated output. A 120A fuse is required on the power feed. For builds adding this amp to an existing system, verify total current load against the charging system's sustained output before finalising the install.
The HDPG4K 4 AWG power and ground kit is the correct wiring solution for this application.
The Bottom Line
The highest-output compact motorcycle amplifier that fits a standard Harley Touring fairing amp tray — 350W × 4 at 2Ω, 700W × 2 bridged, in the same profile as the FLX1000.4. Requires 4 AWG wiring infrastructure. Ready to upgrade? Add to cart above. For builds that need the output of the FLX1400.4 without the 4 AWG wiring requirement, the FLX1000.4 delivers 254W × 4 at 2Ω from a standard 8 AWG install. For maximum output above this level — and a full lithium battery upgrade — the FLX2000.4 delivers 542W × 4 at 2Ω.
Fitment
| Model | Position | Notes |
|---|---|---|
| Street Glide® / Street Glide® Special | Batwing fairing amp tray | Fits standard fairing amp tray |
| Road Glide® / Road Glide® Special | Shark nose fairing amp tray | Fits standard amp tray positions |
| Ultra Limited® / Ultra Classic® | Fairing amp rack positions | |
| CVO models | Fairing amp rack | See 2024+ Skyline OS note in Technical Specifications tab |
| Harley-Davidson Trike | Fairing, trunk, or saddlebag amp rack | Compatible |
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.
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.
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
| Channels | 4-Channel |
| Amplifier Class | Class D |
| Power Output — 4Ω Stereo @ 14.4V | 225W × 4 RMS |
| Power Output — 4Ω Stereo @ 12.5V | 200W × 4 RMS |
| Power Output — 2Ω Stereo @ 14.4V | 350W × 4 RMS |
| Power Output — 2Ω Stereo @ 12.5V | 300W × 4 RMS |
| Power Output — 4Ω Bridged @ 14.4V | 700W × 2 RMS |
| Power Output — 4Ω Bridged @ 12.5V | 600W × 2 RMS |
| Efficiency | 79% |
| Signal-to-Noise Ratio | 91 dB |
| THD+N (10% rated power) | 0.1% |
| Damping Factor | 200 |
| Frequency Response | 20 Hz–20 kHz (±3 dB) |
| Crossover Modes | LPF / Full Range / HPF (selectable) |
| Crossover Range | 30 Hz–300 Hz |
| Crossover Slope | 12 dB per octave |
| Input Sensitivity | 0.2V–12V |
| Inputs | High-level or Low-level RCA |
| Turn-On Modes | REM / DC Offset |
| Operating Voltage | 8V–16V |
| Current Draw (Music) | 50A |
| Current Draw (Maximum) | 220A |
| Recommended Fuse | 120A |
| Minimum Power Wire Gauge | 4 AWG |
| Weather Resistance | Outdoor-rated — moisture and vibration resistant |
| Dimensions — Chassis Only | 168 × 125 × 51 mm (6.6 × 4.9 × 2.0 in) |
| Dimensions — Overall | 200 × 125 × 51 mm (7.9 × 4.9 × 2.0 in) |
| Warranty | 2 years |
Australia Shipping:
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- $500–$2,500 → $14.95
- Over $2,500 → FREE
- Bulky items → +$24.95 surcharge (waived over $2,500)
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Change-of-mind returns: We accept returns within 7 days of delivery on unused, unopened products in original sealed packaging. Restocking fees apply (20–30%). Return shipping is the customer's responsibility.
No returns on opened audio gear, installed items, custom orders, or special-order products. Please check fitment carefully before installing.
Faulty or incorrect items: If you experience an issue, contact us with photos/video and your order number. We'll assess the claim and arrange repair, replacement, or refund for verified faults under the Australian Consumer Law.
Fitment assistance: If you're unsure about compatibility, reach out before ordering—we're happy to help.