Hertz SP 4.500 — Compact 4-Channel Amplifier for High-Efficiency Harley Audio Builds
The Hertz SP 4.500 is a compact, efficient 4-channel Class-D amplifier tailored for motorcycle audio systems that run high-sensitivity speakers and need clean power without the complexity of oversized amps. With an IP55 weather-resistant rating and a low-profile chassis, it fits easily into Harley Touring fairings while delivering reliable performance at volume.
Key Features
- 90 W x 4 RMS @ 4 Ω — ideal for powering high-efficiency SPL speakers.
- 130 W x 4 RMS @ 2 Ω — additional headroom for demanding systems.
- Bridged Mode: 260 W x 2 RMS when running 2-channel configurations.
- IP55 weather resistance protects against water, dust, and road grime.
- Ultra-compact chassis (196 × 131 × 49 mm) fits tight Harley fairings.
- High-level and low-level inputs for flexible system integration.
- Selectable crossovers for high-pass, low-pass, or full-range operation.
Why It Works on Harleys
- Perfect match for high-efficiency speakers like Hertz SX and SV series.
- Compact size allows clean installation in Street Glide and Road Glide fairings.
- Weather-ready design handles open-air motorcycle environments.
- Efficient power draw suits bikes running stock or mildly upgraded charging systems.
Recommended System Use
- Front Stage: Powers 6.5″ coaxials or SPL midranges with ease.
- Full Bike System: Run front + rear speakers on one amplifier.
- Active Setups: Use two channels for mids and two for tweeters when DSP-controlled.
Fitment
- Designed for Harley-Davidson Touring motorcycles
- Suitable for Street Glide, Road Glide, Ultra Limited and CVO models
- Fits factory fairings, amp trays, or aftermarket amp plates
Specifications
| Channels | 4 |
| RMS Power @ 4 Ω | 90 W × 4 |
| RMS Power @ 2 Ω | 130 W × 4 |
| RMS Power (Bridged) | 260 W × 2 |
| Frequency Response | 10–45,000 Hz |
| Signal-to-Noise Ratio | > 100 dB |
| Input Sensitivity | 0.2–5 V |
| Crossovers | HPF / LPF / Full-Range |
| Dimensions | 196 × 131 × 49 mm |
| IP Rating | IP55 |
Need System Design Help?
The SP 4.500 is ideal for efficient SPL setups. We can help you match speakers, crossovers, and DSP settings to create a clean, balanced system for your Harley.
Shipping
Australia Shipping:
- Under $500 → $19.95
- $500–$2,500 → $14.95
- Over $2,500 → FREE
- Bulky items → +$24.95 surcharge (waived over $2,500)
Fast dispatch from Brisbane. Same-day shipping on in-stock orders before 1pm AEST.
Return policy
Change-of-mind returns: We accept returns within 7 days of delivery on unused, unopened products in original sealed packaging. Restocking fees apply (20–30%). Return shipping is the customer’s responsibility.
No returns on opened audio gear, installed items, custom orders, or special-order products. Please check fitment carefully before installing.
Faulty or incorrect items: If you experience an issue, contact us with photos/video and your order number. We’ll assess the claim and arrange repair, replacement, or refund for verified faults under the Australian Consumer Law.
Fitment assistance: If you’re unsure about compatibility, reach out before ordering—we’re happy to help.