Cicada Rebuild Stage 1: Why Our Demo Bike Is Running Two Amplifiers

Cicada Rebuild · Stage 1

Our 2021 Road Glide Special demo bike is getting a full Cicada Audio rebuild, and stage one starts with the amplifiers and the electrical foundation to support them. Two amps are going in, a Cicada FLX1400.4 for the four-channel front and rear speaker system and a Cicada FLX1600.1 for the dedicated saddlebag mid-bass stage, replacing the single amp and dual sub kits from the bike's original SoundStream build. Here's why we picked these two, and what each one is actually for.

Picking Up Where the Last Build Left Off

If you read the original demo bike build, you'll know the SoundStream system measured 112.8 dB running entirely from the stock Harley electrical system, with no auxiliary battery. It's a strong result, and it proved the point: the right components, properly installed and tuned, get you a long way before you start rebuilding the electrical system. That 112.8 dB was recorded under our own test setup; when the Cicada build is finished we'll measure it again with the same gear, microphone position and method, so the before-and-after is a fair comparison rather than two unrelated numbers.

The Cicada rebuild is the next step. Same bike, same philosophy, but with more headroom in every part of the system: more amplifier power, full DSP control, purpose-built mid-bass drivers instead of sealed sub enclosures eating the whole saddlebag, and this time an upgraded power foundation to feed it all. We're documenting it stage by stage as the parts go in, starting with the two amplifiers that will power the speaker system.

Cicada FLX1400.4: The Main Four-Channel Amplifier

The Cicada FLX1400.4 is a high-output 4-channel Class-D amplifier rated at 350W RMS per channel at 2 ohm, or 1,400W total. It's the four-channel workhorse on this build, driving the front and rear speaker stages from a compact chassis that mounts under the fairing rather than needing a saddlebag or remote location.

On this build, both the FLX1400.4 and the FLX1600.1 mount under the fairing on an XEL Custom Cycles amp rack made for 2015 to 2023 Road Glide models, chosen specifically for a dual-amplifier install. Whilst you do need to modify the original bracket, it's a very clean and simple installation process. Cicada's own model-specific Road Glide rack is still an excellent choice for a conventional single-amp install; the XEL rack is here because this build puts two amps under the fairing.

On this build, the FLX1400.4 drives the front and rear speaker stages: two front component channels for the fairing and two rear component channels for the saddlebag lids, going in at a later stage of this build. Four dedicated amplifier channels mean the front and rear speaker positions don't have to share channels or give up the rear stage to a bridged mid-bass output. The amp's built-in HPF and LPF filters can set basic protection during install, while each component kit keeps its own passive crossover between the mid-bass and tweeter on that side. The DSP in the next stage handles the final high-pass targets, EQ, levels and time alignment, and the amp filters can then be set to full range or left in place as backup protection.

Cicada FLX1600.1: Dedicated Power for the Mid-Bass Stage

The Cicada FLX1600.1 is a mono Class-D amplifier rated at 1,600W RMS at 2 ohm, or 950W at 4 ohm. Its job on this build is straightforward: power the mid-bass drivers replacing the SoundStream system's saddlebag subwoofer kits.

We could use a bridged four-channel amp for mid-bass, but each bridged output consumes two amplifier channels. That would either give up the rear stage or need another amplifier anyway. The FLX1600.1 lets the FLX1400.4 keep all four channels for the front and rear speakers, while providing a separate high-power mono channel with its own HPF and LPF filtering for the saddlebag mid-bass stage.

The build uses two 4 ohm CMB10.S4NEO mid-bass drivers, one in each saddlebag. Wired in parallel they present a 2 ohm load to the FLX1600.1, so at its 1,600W rating the two equal drivers share roughly 800W each, matching their published RMS rating. Because both drivers run from the one mono channel they receive the same processed signal, so they can't be levelled or time-aligned independently left to right. That's the trade-off for giving the mid-bass its own dedicated high-power amplifier rather than a shared or bridged channel.

The FLX1600.1 also gets a Dube's Custom Street Machines remote level control in the fairing. The Cicada-compatible version plugs straight into the mono amp and gives on-bike adjustment of the saddlebag mid-bass level, with power and clip indicator lights. It controls the FLX1600.1 stage only, so you can trim how much mid-bass you're running for different music or riding conditions without touching the front and rear speaker levels. It's a remote level control, not a bass boost: it adjusts the level sent to the amp, it doesn't add power or replace correct gain, crossover and DSP setup, and it's set so its top position won't push the FLX1600.1 past the safe output dialled in during tuning.

Like the FLX1400.4, the FLX1600.1 requires 4 AWG wiring, with a 100A fuse recommended on its feed. Running both amps from the one bike means the wiring has to be planned as a system, not bolted on amp by amp, which is exactly what stage one is about getting right before anything downstream gets connected.

Why Two Amps Instead of One

It's a fair question. A single high-power 4-channel amp with two bridged channels would be simpler to install. We went with two dedicated amps so the amplification matches the system: the FLX1400.4 gives each left and right front and rear speaker position its own amplifier channel, with the mid-bass driver and tweeter on each side sharing that channel through their passive crossover. The FLX1600.1 then powers the pair of saddlebag mid-bass drivers as one dedicated mono stage. Neither amp is bridged or doing double duty.

It also sets up the next stage of this build properly. With a dedicated mid-bass channel already in place, the DSP processor going in next can apply time alignment, crossover and EQ to that mid-bass channel as its own zone, without working around a bridged pair borrowed from the rear stage.

Why 4 Ohm Speakers, Not 2 Ohm

The FLX1400.4 is rated higher at 2 ohm than at 4 ohm: 350W per channel versus 225W per channel at a 14.4V supply. On paper, running 2 ohm speakers looks like the easy way to more power for free. We're running 4 ohm on this build, and it's worth explaining why.

A 2 ohm load lets the amplifier deliver more power, but that extra output also raises heat and electrical demand. It does not mean the amp's battery current simply doubles in every listening condition: actual current depends on volume, programme material, amplifier efficiency and how often the system approaches rated output. Cicada publishes a 50A musical-current figure, a 220A maximum figure and a 120A recommended fuse for the FLX1400.4. Those figures describe different operating conditions, and shouldn't be read as a simple calculation of charging-system headroom.

Powering Two Amps from One Bike

Running this many amps isn't just about the charging system, it's about the whole electrical foundation. The bike keeps its factory charging system, but the Cicada rebuild swaps the stock battery for a Braille Green Lite G30H lithium battery to support the short, high-current audio peaks these amps draw and to hold voltage steadier under load. That's different from saying the whole electrical system stays factory. Power distribution runs through the Cicada HDPG2KD dual-amp power and ground kit. A 200A master fuse sits as close to the battery as practical, protecting the 2 AWG main feed up to the distribution block. From the block the power splits into two individually fused 4 AWG legs: a 120A fuse to the FLX1400.4 and a 100A fuse to the FLX1600.1, each matched to that amplifier's recommended rating. Each branch fuse protects its own 4 AWG leg where the feed steps down from the 2 AWG main, so it isn't just spare over-protection. The 120A fuse for the FLX1400.4 is sourced separately, since the HDPG2KD's standard fuse assortment (100A, 150A and 200A) doesn't include that value. It's the kind of detail that's invisible in the finished bike and is also the difference between a properly protected installation and one left vulnerable to voltage drop, heat or wiring faults.

What's Next

With both amplifiers wired in, the next stage covers the signal side: a dedicated DSP processor to handle time alignment, EQ, and crossover control across every channel, followed by the front and rear speaker stages themselves. We'll cover each as it goes in.

Frequently Asked Questions

Browse the full Cicada Audio range, or check out the FLX1400.4 and FLX1600.1 to start planning your own build.