Velocity Stage 4 Ultimate A2B Plug & Play Amp And Speaker Package with Modular Subwoofer Kit For 2026 Harley Davidson® CVO Street Glide ST Motorcycles

For CVO Street Glide ST Motorcycles

Can you hear your factory Harley speakers loud and clear at highway speeds?

We didn’t think so.

Tired of blowing those factory speakers just trying to hear them?

Of course you are! These are common issues we hear at Volunteer Audio, and we’re here to offer a solution that will blow you away.

Our Volunteer Audio Velocity Razor Stage 4 amplifier, speaker, and subwoofer system is designed to transform your audio experience. This package allows you to keep your factory radio while upgrading your sound system. To get the full potential from your new amplifier and speakers, a flash is required to optimize performance.

With this setup, you’ll enjoy music that’s loud, clean, and clear at highway speeds while adding the low-frequency impact your factory system is missing.

What Makes This System Exceptional?

• High-Output Performance: The Velocity Razor system is designed specifically for demanding motorcycle audio applications, providing the output and clarity needed to overcome wind, exhaust, and road noise.
• Premium Neodymium Speakers: Velocity Razor Coax Neo speakers feature lightweight neodymium motors and integrated tweeters that deliver crystal-clear vocals, detailed highs, and powerful midbass.
• Complete Front & Rear Sound: With RCN65 speakers in the upper fairing and RCN69 6x9” speakers in the saddlebag lids, the Stage 4 system delivers powerful front sound with enhanced rear output and midbass for a fuller listening experience.
• True Low-Frequency Performance: The American Hard Bag IP24SWEV Modular Subwoofer Kit adds deep, musical bass and low-frequency impact that full-range motorcycle speakers simply can’t reproduce on their own.
• Compact, Efficient Amplification: The Velocity Razor Pro amplifier delivers the clean power needed to drive the system while maintaining a compact footprint ideal for motorcycle installations.

Package Includes:

• Pre-Wired Velocity Razor Pro RZP2000.6 Amplifier: Gains and filters are professionally adjusted for your factory Skyline OS Infotainment radio.
• Volunteer Audio HD-A2B8 Interface: Seamlessly integrates with your Harley-Davidson®, expertly tuned for Velocity Razor systems.
• 1 Pair of Velocity Razor Coax Neo RCN65 6.5” Upper Fairing Speakers: High-output neodymium coaxial speakers designed to deliver crystal-clear vocals, detailed highs, strong midbass, and impressive output at highway speeds.
• 1 Pair of Velocity Razor Coax Neo RCN69 6x9” Saddlebag Lid Speakers: Premium high-output neodymium coaxial speakers engineered to provide exceptional midbass, outstanding clarity, and the output needed to keep your music loud and clean on every ride.
• 1 Pair of Volunteer Audio IP-24-LIDKIT-V 6x9” Saddlebag Speaker Cut Kits: Precision-engineered cut kits for installing the Velocity Razor Coax Neo RCN69 speakers into factory non-speaker saddlebag lids. Includes templates, black grilles, and mounting hardware.
• American Hard Bag IP24SWEV Modular Subwoofer Kit: Complete modular bass system featuring the Velocity Performance Edition 10-inch subwoofer, engineered specifically for the American Hard Bag enclosure to deliver tight, musical bass with outstanding impact and low-frequency performance.
• Velocity Razor Power/Ground Harness: Provides clean, reliable power and grounding for optimal amplifier performance.

Why Choose Volunteer Audio?

• Pre-Configured Kit: We complete all the prep work, setting gains and filters so you don’t have to. The kit arrives as close to finished as possible, making installation straightforward.
• Easy Installation: Includes mounting hardware and clear step-by-step videos. You only need to mount the amplifier, connect the wiring under the seat and to the battery, install the speakers and subwoofer, and complete the required flash.
• Lifetime Tech Support: We offer lifetime support for any items purchased from us, ensuring you get the help you need.

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American Hard Bag Modular Bass System

Velocity Performance Edition

Engineered Specifically for the American Hard Bag Enclosure

The Velocity 10-inch subwoofer wasn’t selected from an existing catalog.

It was engineered specifically for the American Hard Bag enclosure, creating a system where the driver, enclosure, and passive radiator were developed together as a complete acoustic package.

Rated at 300 Watts RMS and 600 Watts Maximum Power, the Velocity subwoofer features an injection-molded cone, Santoprene surround, oversized 56-ounce ferrite motor, and a 38 mm TIL voice coil to deliver exceptional punch, musicality, and long-term reliability.

If your playlist is filled with country, rock, blues, classic rock, or live recordings, the Velocity Performance Edition delivers outstanding impact and natural musical accuracy.

Ideal For: Country, Rock, Classic Rock, Southern Rock, Blues, and Live Recordings

Performance Highlights:

• 300 Watts RMS

• 600 Watts Maximum Power

• Frequency Response: 20–400 Hz

• Injection-Molded Cone

• Santoprene Surround

• 38 mm TIL Voice Coil

• 56 oz Ferrite Magnet

Expect:

• Tight, punchy bass

• Incredible kick drum impact

• Excellent bass guitar definition

• Fast transient response

• Natural, musical low frequencies

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HD-A2B8 Amplifier Replacement Interface

Compatibility:

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

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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.

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Manufacturer:

• Designed and manufactured by SeirenHD exclusively for Volunteer Audio.

• Engineered and manufactured in the USA.

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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

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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.

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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

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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

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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

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Velocity Razor Pro Amplifier

The Velocity Razor Pro amplifier is designed for high-performance motorcycle audio systems where space is limited but clean power and serious output are essential.

Its compact, high-efficiency Class D design provides the power needed to properly drive the Velocity Razor Coax Neo speakers while helping reduce unnecessary heat and electrical demand on the motorcycle’s charging system.

Paired with the Velocity Razor Coax Neo RCN65 upper fairing speakers and RCN69 6x9” saddlebag speakers, the Razor Pro amplifier provides the power and control needed to maintain crystal-clear vocals, detailed highs, powerful midbass, and impressive output at highway speeds.

Add the American Hard Bag IP24SWEV Modular Subwoofer Kit, and the Stage 4 system gains the low-frequency extension and impact needed to create a complete, full-range motorcycle audio experience.

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Ready to Elevate Your Ride?

At Volunteer Audio, we’ve combined the Velocity Razor Pro amplifier, Velocity Razor Coax Neo RCN65 and RCN69 speakers, and the American Hard Bag IP24SWEV Modular Subwoofer Kit to create a Stage 4 system that delivers serious performance from top to bottom.

The RCN65 speakers provide crystal-clear sound from the upper fairing, the RCN69 6x9” speakers add powerful rear output and midbass from the saddlebag lids, and the Velocity Performance Edition 10-inch subwoofer brings in the tight, musical low-frequency impact that completes the system.

The result is incredible volume, exceptional clarity, strong midbass, and powerful bass that you can hear and feel whether you’re cruising around town or running down the interstate.

Ready for a sound transformation? Let Volunteer Audio help you hear your Harley the way it was meant to sound.