Cicada Audio CMB8.S4 — 8" High-Power Motorcycle Mid-Bass Driver (4Ω, 500W RMS)
| Size | 8 · Mid-bass |
| Impedance | 4 Ohm |
| Power | 500W RMS |
| Year Range | 2014-2023, 2024+ |
| Location | Saddlebags |
8" mid-bass driver for Harley-Davidson Touring custom saddlebag builds — 500W RMS, Y30 ferrite motor, 4Ω
The Cicada Audio CMB8.S4 is an 8-inch mid-bass driver built for custom saddlebag enclosures, stretched bags, and bespoke Harley Touring sound systems. With 500W RMS power handling, a Y30 ferrite ceramic motor, a 63.5mm (2.5") 6-layer Black Coat™ OFC voice coil, Cicada's vented voice coil gap, and an advanced voice coil heat sink, it delivers controlled, high-output mid-bass performance in builds where the 8" format is the enclosure design starting point. Designed to run bridged off a Cicada FLX1000.4 (approximately 508W bridged into 4Ω per pair) or FLX1400.4 with gain control.
Who This Is For
The CMB8.S4 is for Harley-Davidson Touring riders building a custom saddlebag sound system around an 8" enclosure — stretched bags, fabricated pods, or a purpose-built 8" lid kit — and for Road Glide riders targeting the lower fairing position where an 8" driver suits the available cavity. If your build can accommodate a 10" driver and your amplifier can deliver 700–800W bridged into 4Ω, the CMB10.S4 (800W RMS) offers greater output and deeper extension in the same ferrite motor architecture. The CMB8.S4 is the correct choice when enclosure volume, saddlebag dimensions, or amplifier power budget sets the constraint at 500W RMS.
What This Is Best For
- Custom saddlebag enclosures tuned to the 8" format — At 99.5mm (3.9") mounting depth and 187.5mm (7.38") mounting diameter, the CMB8.S4 fits cleanly into fabricated 8" enclosures without internal volume compromises from an oversized driver. Mid-bass response stays controlled because the driver is matched to the enclosure parameters, not squeezed into a volume designed for something else. On the road: lower extension and output remain consistent — the enclosure is working as designed, not fighting a driver it wasn't tuned to.
- Bridged 4-channel amplifiers delivering 500W RMS per channel pair — The 4Ω voice coil is designed to run bridged off a Cicada FLX1000.4 (254W × 4 @ 2Ω, approximately 508W bridged into 4Ω) or FLX1400.4 with gain set appropriately. Matching the amplifier output to the driver's RMS rating eliminates the two primary causes of mid-bass driver failure: sustained underpowering from amplifier clipping, and sustained overdriving past the thermal limit. On the road: full rated output at highway speed without voice coil thermal stress, even across extended freeway cruising in summer heat.
- Y30 ferrite ceramic motor for thermal and mechanical stability — The Y30 ferrite motor maintains consistent magnetic flux density across the full temperature range a saddlebag enclosure experiences — from a cold winter start through a sustained summer afternoon run. Ferrite magnets carry no demagnetisation risk from shock or heat cycling, which matters for a driver mounted in an external position exposed to direct sun, engine vibration, and road impact. On the road: motor performance doesn't degrade over a long touring day — output consistency at destination matches output at departure.
- Vented voice coil gap and advanced heat sink for sustained power handling — At 500W RMS, thermal management determines whether a mid-bass driver delivers consistent output or progressively compresses over a ride. The CMB8.S4 combines a vented voice coil gap — which draws cooler air through the former during each excursion cycle — with an advanced voice coil heat sink that conducts thermal energy into the motor structure. On the road: sustained output at rated power doesn't produce the gradual loudness roll-off that characterises unvented drivers running near their thermal ceiling after 30–60 minutes at high volume.
- 35 Hz – 3 kHz coverage for full-range saddlebag staging — The CMB8.S4's low-end extension to 35 Hz (±5 dB) means a correctly tuned custom enclosure can deliver meaningful bass output without a dedicated subwoofer in many builds. The 3 kHz upper limit provides clean crossover overlap with a high-pass filtered fairing speaker or tweeter stage. On the road: a two-driver saddlebag system built around the CMB8.S4 delivers full-range output at highway speed — sub-bass extension below 40 Hz fills the low-end that wind noise and open-air riding conditions would otherwise absorb.
CMB8.S4 or CMB10.S4 — which driver is right for your build?
The deciding factor is enclosure volume and amplifier output, not just available space. The CMB10.S4 (10", 800W RMS) delivers greater output and lower extension — but requires a larger air volume, a deeper mounting depth of 110mm (4.3"), and an amplifier capable of 700–800W bridged into 4Ω per pair. The CMB8.S4 (8", 500W RMS) is the right call when your saddlebag build targets the 8" format, or when your amplifier is bridging at or around 500W per pair. Both drivers use the same Y30 ferrite motor architecture and Black Coat™ OFC voice coil — the enclosure volume, mounting depth, and amp match are what separate them in an actual install. If you're unsure which suits your build, contact MAA before ordering.
Fitment
| Model | Years | Position |
|---|---|---|
| Street Glide® / Street Glide® Special | 2014–2025 | Custom Saddlebag Enclosure |
| Road Glide® | 2015–2025 | Custom Saddlebag Enclosure |
| Ultra Limited® | 2014–2025 | Custom Saddlebag Enclosure |
| Electra Glide® Ultra Classic™ | 2014–2023 | Custom Saddlebag Enclosure |
| CVO™ Street Glide® | 2014–2025 | Custom Saddlebag Enclosure |
| CVO™ Road Glide® | 2015–2025 | Custom Saddlebag Enclosure |
| CVO™ Limited | 2014–2025 | Custom Saddlebag Enclosure |
| Road Glide® (Lower Fairing) | 2015–2025 | Lower Fairing (Custom Mount Required) |
The Bottom Line
The CMB8.S4 is the right mid-bass driver for Harley Touring builds where the 8" format is the engineering constraint — custom saddlebag enclosures, stretched bags, lower fairing builds on Road Glide®, and any system where a 10" doesn't fit the available volume or available power. Bridged off a Cicada FLX1000.4, it operates at rated 500W RMS without compression or thermal stress. If your build can step up to a 10" driver and 800W bridged, the CMB10.S4 is the natural upgrade in the same motor architecture. Contact MAA to confirm which driver fits your specific enclosure before ordering.
The CMB8.S4 is built around a Y30 ferrite ceramic magnet motor and a 63.5mm (2.5") 6-layer Black Coat™ OFC voice coil — a mid-bass architecture designed for controlled excursion, thermal durability, and consistent output at sustained power levels. Each component reflects a deliberate engineering decision for the motorcycle saddlebag environment.
Y30 Ferrite Ceramic Motor
The CMB8.S4 uses a Y30 ferrite ceramic magnet motor — the same proven magnetic architecture as the CMB10.S4. Y30 ferrite magnets are thermally stable, mechanically robust, and free of the demagnetisation risks that can affect neodymium designs under sustained thermal cycling. In a saddlebag enclosure exposed to direct sun, engine heat, and road vibration over a full touring day, that stability directly translates to consistent magnetic flux density across the entire ride. On the road: motor performance at hour six of a touring day matches hour one — magnetic output doesn't degrade with heat or vibration the way thermally sensitive magnet types can under sustained high-power operation.
2.5" Black Coat™ OFC Voice Coil
The 63.5mm (2.5") voice coil uses 6-layer Black Coat™ Oxygen-Free Copper (OFC) construction wound on a precision former. Six conductor layers instead of the conventional two or four increase total cross-section, which reduces resistive heating per layer at a given power level and extends the coil's sustained power ceiling. Black Coat™ is a thermal barrier and corrosion-resistant treatment applied to the coil windings that improves heat dissipation and protects against moisture ingress — a relevant concern in an external saddlebag position. On the road: the voice coil handles 500W RMS continuously without progressive thermal compression — output level at the end of a highway run matches what you set at the start.
Vented Voice Coil Gap and Advanced Voice Coil Heat Sink
Thermal compression — the gradual output reduction that occurs as a voice coil heats under sustained power — is the primary performance limiter in high-powered mid-bass applications. The CMB8.S4 addresses this with a vented voice coil gap that draws cooler air through the coil former during each excursion cycle, and an advanced voice coil heat sink that conducts thermal energy away from the coil and into the motor structure. Together, these significantly raise the thermal threshold at which compression becomes audible. On the road: two hours of highway cruising at full volume doesn't produce the gradual loudness roll-off that characterises unvented drivers running near their thermal limit — output stays consistent across the full ride.
Heavy Duty Die-Cast Aluminium Basket
The heavy duty die-cast aluminium basket provides the rigid mechanical reference frame that accurate mid-bass reproduction requires at high excursion. Die-cast construction eliminates the flex and parasitic resonance that pressed-steel baskets introduce at higher output levels, and aluminium's thermal conductivity contributes to heat dissipation from the motor and voice coil assembly. Under sustained motorcycle vibration, a rigid basket also preserves voice coil and gap alignment across the driver's working life. On the road: the driver maintains geometric accuracy under the combined stress of high excursion, sustained power, and continuous road vibration — the mechanical conditions that separate purpose-built motorcycle drivers from repurposed car audio components.
Why Ferrite — and Why It's the Right Choice for This Build
Neodymium motors offer greater magnetic flux density per unit weight, which makes them attractive where mass is the constraint. For a 500W RMS 8" mid-bass driver in a saddlebag enclosure, that trade-off reverses: enclosure dimensions are set by acoustic parameters and available space, not motor weight; and the Y30 ferrite motor's thermal stability, immunity to demagnetisation, and long-term consistency under vibration all outweigh the weight reduction a neodymium alternative would provide. The CMB8.S4 is not the lighter option — it is the more robust one for sustained high-output saddlebag use. If the specific application requires a neodymium motor (Tour-Pak builds with strict weight limits, for example), the CMB10.S4NEO offers a neodymium-motor 10" alternative in the same Cicada Audio range.
Technical Specifications
| RMS Power Handling | 500W |
|---|---|
| MAX Power Handling | 1,000W |
| Impedance | 4Ω |
| Motor Type | Y30 Ferrite Ceramic |
| Voice Coil Diameter | 63.5mm (2.5") |
| Voice Coil Construction | 6-Layer Black Coat™ OFC |
| Frequency Response | 35 Hz – 3 kHz (±5 dB) |
| Sensitivity | 87.2 dB (1W/1M) |
| Total Diameter | 211mm (8.3") |
| Mounting Diameter | 187.5mm (7.38") |
| Mounting Depth | 99.5mm (3.9") |
| Basket Construction | Heavy Duty Die-Cast Aluminium |
| Thermal Management | Vented Voice Coil Gap + Advanced Voice Coil Heat Sink |
In the Box
- 1× Cicada Audio CMB8.S4 Mid-Bass Driver
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- Under $500 → $19.95
- $500–$2,500 → $14.95
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