HD-A2B8 – 10-Channel Amplifier Replacement Interface

(8 Analog + 2 Digital Outputs with Full DSP and Factory Subwoofer Support)

⸻

Compatibility:

• Designed for Harley-Davidson models equipped with the Skyline OS Infotainment Unit.

⸻

Purpose:

• Allows for the removal of the stock amplifier.

• Facilitates the installation of higher power aftermarket amplifiers.

• Maintains compatibility with factory-installed Rockford Fosgate subwoofers and rear-mounted secondary amplifiers.

⸻

Manufacturer:

• Designed and manufactured by SeirenHD exclusively for Volunteer Audio.

• Engineered and manufactured in the USA.

⸻

Pre-Tuned for Plug-and-Play Performance

The HD-A2B8 interface from Volunteer Audio and SeirenHD is ready to install right out of the box—no tuning required for standard systems.

Already optimized for immediate use:

• Flat EQ Curve – Delivers a clean, uncolored audio signal

• Pre-Set Output Levels – Optimized to run clean at full volume with zero clipping

• Speed-Controlled Volume – Fully retained and pre-configured to match factory behavior

• Fader Support – Works immediately without any setup

• All Factory Features Intact – Including navigation prompts, radio EQ selections, and more

Tuning is optional, only necessary when:

• Activating crossovers

• Using the 31-band or 10-band EQ to customize for specific speaker setups

• Adjusting time alignment or per-channel output levels

⸻

Plug-and-Play Harnessing

The HD-A2B8 includes a harness that connects directly to all factory speaker wiring with zero modification to your motorcycle.

For expanded setups, additional plug-and-play harnessing is available below:

• Underseat Harness – Pins into the factory plug on base model bikes

• Lid Disconnect Harness – Clean, quick-disconnect solution for 6x9 lid speaker installations

• Tour Pack Harness – Adds plug-and-play rear audio for tour pack installations

• Lower Fairing Harness – Simple solution for adding speaker pods to your lower fairings

All harnessing options are pre-configured and labeled for quick installation and available for purchase below.

⸻

Integration Features:

• Utilizes the OE A2B chip for seamless factory integration

• Supports all factory infotainment updates

• Retains full factory functionality, including:

• Fader

• EQ selections with DSP profile adjustments

• Speed-controlled volume

• Navigation prompts

• Digital A2B subwoofer output for HD Audio by Rockford systems

⸻

DSP Specifications:

• 10 Output Channels with Full DSP Control:

• 8 Analog RCA Outputs

• 2 Digital A2B Outputs (for Rockford subwoofers)

• Equalization:

• Per-channel 31-band graphic EQ or 10-band parametric EQ

• Global 7-band parametric EQ mirrors infotainment custom EQ settings

• Time Alignment:

• Independent delay settings for every channel

• Crossover Control:

• Independent high-pass and low-pass filters per output pair

• Level Adjustment:

• Individual channel-level control for precise tuning

⸻

Technical Specifications:

• RCA Outputs:

• 8 Channels, 4v RMS

• Front, Rear, Subwoofer, and Auxiliary output configuration

• Frequency Response: 20 Hz – 24 kHz

• Signal-to-Noise Ratio: 112 dB

• DSP Resolution: 32-bit

• Operating Voltage: 6–28 volts

• Current Draw:

• Idle: 14 µA

• Full Power: 300 mA

• Warranty: 1 Year

⸻

DSP Tuning Access:

• All DSP settings and tuning are available at: http://eq.seirenhd.com

• Includes preloaded DSP tunes for:

• Hertz Audio Systems

• Velocity Audio Systems

• Extreme Audio Systems

• …and many more manufacturers coming soon!

• Easily pair with any universal amplifier for fast, optimized installation.

⸻

Coming Soon:

• Automatic DSP tuning via upcoming software update

• Additional tuning features and enhancements under active development

⸻

Vehicle Compatibility:

• 2024-Up Base Model Street Glide

• 2024-Up Base Model Road Glide

• 2023.5-Up CVO Street Glide

• 2023.5-Up CVO Road Glide

• 2024-Up CVO ST Models

2023.5-Up Signature A2B Packages

Hertz HD24H 6X9″ Saddlebag Speaker Installation Kit with Wiring for 2023.5-Up Harley Davidson® Touring Models

Volunteer Audio 10-Channel HD-A2B8 Amplifier Replacement Interface for 2023.5-Up Harley Davidson® Motorcycles

Hertz HD24H 6X9″ Saddlebag Speaker Installation Kit with Wiring and Hardware Pack for 2023.5-Up Harley Davidson® Touring Models

Hertz SX165NEO 6.5" + SX690H NEO 6x9" 4-Ohm Water Resistant Coax Speakers Modified for 2023-Up Harley Davidson® CVO Only