Why 2023.5+ Harley Audio Upgrades Need an A2B Interface

Reference Series · A2B

Harley A2B Audio Explained: When a 2023.5+ Bike Needs an Interface

What Changed on 2023.5+ Harley Touring Models

From the 2023.5 production split onward (starting with the redesigned CVO Street Glide and CVO Road Glide, then the standard Street Glide and Road Glide for 2024), Harley moved the audio path onto a digital A2B (Automotive Audio Bus) network. Instead of a conventional analogue signal travelling through speaker wires between the head unit and amplifier, audio and control data are carried digitally across a managed bus. That is why the analogue integration methods used on 2014 to early-2023 bikes do not translate directly to Skyline-equipped models.

What A2B Is, and Where It Sits

A2B is the transport network, not the processor. The factory signal processing (EQ, limiting, volume management) happens in the source, the factory amplifier and the associated audio modules; the A2B bus carries the digital audio and control data between those devices. Understanding that distinction is the key to the whole topic: you are not trying to reach "inside" the bus, you are deciding where to take a usable signal from.

Why a Basic Analogue Tap Is Limited

A conventional line output converter cannot attach to the digital A2B bus at all. An analogue signal does exist downstream of the factory amplifier, at the speaker outputs, but by that point it has already been processed and amplified: equalised for the factory speakers, dynamically limited to protect OEM components, and volume-scaled. Tapping there gives you a finished, already-amplified signal rather than a clean starting point, which typically means reduced headroom, tonal balance that shifts with volume, and a system that will not tune cleanly.

When You Don't Need an Interface

Not every Skyline upgrade needs A2B. A confirmed, compatible speaker-only replacement that keeps the factory amplification does not require an interface. If your plan is simply better fairing speakers on the factory system, you can do that without touching the A2B path.

When an A2B Interface Is the Right Foundation

An A2B interface becomes the correct route when you are adding or replacing amplification, that is, bypassing or replacing the factory amplifier to obtain predictable low-level outputs for an aftermarket amplifier or DSP. The interface installs in the factory amplifier location, communicates directly with the A2B system, and converts the supported audio channels into predictable analogue RCA outputs, while retaining supported factory functions such as volume, balance, fader, chimes and the factory EQ presets. It does not make the system louder; it makes everything downstream predictable and controllable.

Two interface ecosystems are commonly used, each with its own Cicada amplifier harness:

• The NAV-TV ZEN-H, which supplies eight channels of 5V analogue RCA output; Cicada's 24HDNAVTVA2B harness connects it to Cicada amplifiers.
• The Volunteer Audio (SeirenHD) HD-A2B, which similarly replaces the factory amplifier and supplies analogue outputs, with a preconfigured flat output on supported standard systems; Cicada's 24HDVAA2B / CHDVAA2B harness connects it to Cicada amplifiers.

Why Some Cicada Kits Say "A2B Interface Not Included"

You will see some Cicada Skyline system kits state that an A2B interface is not included. That does not mean the system is designed to be installed without one. It means the amplifier, speakers and installation hardware are packaged separately from the interface, so the installer or customer can choose between compatible A2B solutions (the NAV-TV ZEN-H or the Volunteer Audio / SeirenHD HD-A2B) and add the matching Cicada interface-to-amplifier harness to complete the build. The interface is selected and purchased separately, not omitted from the finished system.

ZEN-H vs ZEN-H PRO

Within the NAV-TV range, Motorcycle Audio Australia supplies two versions:

• ZEN-H: the A2B interface with eight channels of analogue RCA output. The right choice when signal processing happens downstream, on a DSP-equipped amplifier (such as the Cicada FLX PRO series) or a standalone DSP.
• ZEN-H PRO: the same interface with a built-in 8-channel DSP (time alignment, crossover configuration, parametric EQ and phase), tuned on a PC. It reduces the need for a separate DSP module where fairing space is limited.

Both install in the factory amplifier location with the same plug-and-play connection; the choice is where you want DSP to sit in the chain.

Confirm Compatibility Before You Buy

A2B compatibility is not simply "2023.5+ Skyline." Confirm the interface against:

• The exact model year
• The standard or CVO audio package
• Whether a factory amplifier is fitted, and which one
• The number of factory audio channels / zones
• The installed infotainment software and firmware

Getting this right up front is what keeps the install clean and the result predictable.

What Comes After the Interface

Once a proper A2B interface is providing predictable analogue outputs, the rest of the system design follows the usual path: amplifier selection matched to riding conditions, correct gain structure, speaker selection, and DSP strategy for crossover points, staging and tonal balance. Signal first, everything else second. To continue from here, work through the Motorcycle Audio Tuning Series, and for the practical LOC-versus-A2B comparison see LOC vs A2B Interface on 2023.5+ Harley Touring.

Motorcycle Audio Australia. Sound That Rides.