Helix Ci5 S200FM-S2 – 200 mm shallow hybrid woofer with single 2 Ω voice coil
The Ci5 S200FM-S2 belongs to the HELIX COMPOSE i5 series, positioned between the i7 and i3 lines for listeners who want hi-fi sound in the car. The COMPOSE platform adapts universal drivers to modern vehicles while keeping high efficiency, sound quality and dynamics, with impedances matched to HELIX and MATCH amplifiers.
As a hybrid woofer it combines mid-woofer and subwoofer functions, with high excursion (±7.8 mm), power handling and output from a chassis only 47 mm deep – ideal for BMW under-seat and Mercedes bulkhead positions. The glass-sphere-reinforced polymer basket gives stiffness, low self-resonance, reduced flux modulation and heat resistance, and driver development was verified with the Klippel Analyzer System. FlexMount200 adaptors allow fitting in factory positions.
Key Features
- High excursion: ±7.8 mm linear excursion for high SPL and deep bass.
- Hybrid concept: covers roughly 25–500 Hz.
- Single 2 Ω voice coil: for maximum output from the amplifier.
- Shallow build: only 47 mm installation depth.
- Compact outer diameter: cone area of a standard 200 mm chassis.
- Polypropylene cone: lightweight and stiff.
- Reinforced polymer basket: rigid with minimal ringing.
- Powerful magnet: high efficiency and good impulse response.
- Klippel verified: development verified with the Klippel Analyzer System.
- Vehicle applications: under-seat in BMW models and front subwoofer in Mercedes models.
- FlexMount200: car-specific adaptors for original under-seat and bulkhead positions.
Drivers & Construction
200 mm flat woofer with injected polypropylene cone (194 cm² cone area), 38 mm voice coil with 20.6 mm winding height and glass-bead-reinforced polymer basket. Also available as dual-voice-coil version Ci5 S200FM-D2 (2 x 2 Ω).
Acoustic Performance
Power handling 200 W RMS / 400 W max, impedance 1 x 2 Ω (Re 1.8 Ω), frequency response 25–500 Hz, sensitivity 92 dB at 2.83 V/1 m (86 dB at 1 W/1 m). Thiele-Small data: Fs 47 Hz, Qms 9.12, Qes 0.79, Qts 0.73, Cms 297 µm/N, Vas 15.7 l, BL 5.1 Tm, Mms 38 g, Rms 1.29 kg/s, Xmax ±7.8 mm.
Installation Notes
Outer diameter 195 mm (7.68″), installation diameter 173.5 mm (6.83″), installation depth 47.0 mm (1.85″). Vehicle-specific FlexMount200 adaptors are available for original positions.
Technical Specifications
| Power handling RMS / Max. | P |
200 / 400 Watts |
| Impedance | Z | 1 x 2 Ω |
| DC resistance | Re | 1.8 Ω |
| Frequency response | 25 Hz – 500 Hz | |
| Resonance frequency | Fs | 47 Hz |
| Mechanical Q factor | Qms | 9.12 |
| Electrical Q factor | Qes | 0.79 |
| Total Q factor | Qts | 0.73 |
| Compliance | Cms | 297 µm/N |
| Equivalent air volume | Vas | 15.7 L |
| Force factor | B*I | 5.1 Tm |
| Sensitivity | SPL | 92 dB @ 2.83 V / 1m 86 dB @ 1W / 1m |
| Cone area | Sd | 194 cm² |
| Moving mass | Mms | 38 g |
| Cone material | Injected polypropylene | |
| Mechanical resistance | Rms | 1.29 kg/s |
| Voice coil diameter | ø | 38 mm |
| Voice coil winding height | 20.6 mm | |
| Max. linear excursion | Xmax | +/- 7.8 mm |
| Outer diameter | ø | 195 mm / 7.68″ |
| Installation diameter | ø | 173.5 mm / 6.83″ |
| Installation depth | 47.0 mm / 1.85″ | |
| Features | FlexMount200 |
Scope of Delivery
2 x Ci5 S200FM-S2
2 x Mounting material
