Hertz Stage 6 Plug & Play Amp And Speaker Package For 2025 Harley Davidson® CVO Street Glide 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 ALL the time at Volunteer Audio. That’s why we’re here to deliver a sound experience that will truly blow you away. Can you really hear rear speakers when added to your bike? Absolutely! We get this question frequently, and the answer is a resounding YES. Here’s how we ensure you get the full benefit from your rear speakers:

• Optimal Speaker Positioning: For 6x9” speakers, we use custom cut-in kits that elevate the speakers higher in the lid. This not only saves space in your bag but also angles the speakers toward you, improving sound clarity. Most replacement lids don’t do this.
• Proper Powering: We make sure the rear speakers are properly powered so they’re loud enough to be heard even from behind.
• Balanced Sound: While front speakers will always be louder due to their direct orientation, rear speakers add a fuller, surround sound experience with enhanced mid-bass, creating a concert-like atmosphere.

Our Comprehensive Audio Upgrade Package Includes:

• Pre-Wired Amplifier: Gains and filters are adjusted perfectly for your factory Skyline OS Infotainment radio.
• Volunteer Audio HD-A2B8 Interface: Seamlessly integrates with your Harley Davidson.
• 1 Pair of Hertz SX165NEO 6.5” Upper Fairing Speakers: High-quality replacements for your factory speakers.
• 1 pair of Hertz SX690H NEO 6x9” Saddlebag Lid Speakers: Designed for clear sound and durability.
• 1 Pair of Hertz SV165NEO 6.5" Tour Pak Speakers: Designed for clear sound and durability.
• Hertz Power/Ground Harness: Ensures reliable power and grounding.
• Lengthened Rear Backbone Harness and Modified T-Harness: Designed for an optimal fit and function.

Why Choose Volunteer Audio?

• Pre-Configured Kit: We handle all the prep work, including 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. All you need to do is mount the amplifier, connect the wiring to under the seat and battery, and install the speakers.
• Lifetime Tech Support: We offer lifetime support for any items purchased from us, ensuring you have assistance whenever needed.

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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  DSP Tuning Access:
   
  • All DSP settings and tuning are available at: http://eq.sirenhd.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.
   
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  Coming Soon:
   
  • Automatic DSP tuning via upcoming software update
  • Additional tuning features and enhancements under active development

Hertz SP4.900 Amplifier

Our friends at Hertz have released a game changer for motorcycle audio! The Hertz SP4.900 amplifier offers a small footprint but huge output. It’s the most powerful amp available in its size, delivering 160W RMS @ 4Ω and 250W RMS @ 2Ω. With a remarkably low distortion rate of 0.02% THD, it’s the perfect choice for your motorcycle audio system. Technical Specs:

• Output Nominal Power (RMS) @ 14.4 VDC, THD 1%:
  • 4 Ch:
    • 160 W x 4 (4Ω)
    • 250 W x 4 (2Ω)
  • 3 Ch:
    • 160 W x 2 (4Ω) + 500 W x 1 (4Ω)
    • 250 W x 2 (2Ω) + 500 W x 1 (4Ω)
  • 2 Ch:
    • 500 W x 2 (4Ω)
  • Total Power RMS: 1000 W
• Dyno Specs:
  • Box rating: 160 watts at 4Ω, Dyno reads 173 watts at 4Ω
  • Box rating: 250 watts at 2Ω, Dyno reads 288 watts at 2Ω

Ready to Elevate Your Ride?

At Volunteer Audio, we’re committed to providing you with an amazing sound system for your Harley Davidson. Our Stage 4 package is designed for top-notch performance and durability, transforming your motorcycle into a high-quality audio experience. Ready for a sound transformation? Let us help you get there!