Helix Ci5 M50FM-S3 – 50 mm Wideband Speaker with FlexMount50
The Ci5 M50FM-S3 is a 2″ (50 mm) advanced wideband driver from the HELIX COMPOSE platform, which re-engineers universal speakers so they combine universal flexibility with vehicle-specific advantages – “developed inside the vehicle, for the vehicle”. The i5 series sits between i7 and i3 for listeners who want true hi-fi sound, and the 3 Ω design is matched to HELIX and MATCH amplifiers.
Its outer diameter is smaller than that of typical 2″ drivers, so it fits tight OEM openings, angled mounts and housings where 2- or 3-way setups are difficult. Thanks to its broad frequency range it allows layouts without a separate tweeter and is an excellent choice for center, full-range and DSP applications. The silicon-coated paper cone offers internal damping, an aluminum dust cap bonded to the voice coil improves transient response, and a push-pull neodymium magnet raises sensitivity while keeping distortion low.
Key Features
- Compact wideband driver: 2″ driver with flexible physical integration.
- Wide frequency range: 300 – 20,000 Hz, allowing system layouts without a separate tweeter.
- 3 Ω technology: more efficiency and amplifier output with HELIX and MATCH amplifiers.
- Silicon-coated paper cone: high internal damping for good impulse and frequency response.
- Aluminum dust cap: light and rigid, bonded directly to the voice coil for better transient behaviour.
- Rubber surround: specially shaped, with an optimized magnet for large linear excursion (Xlin ±2.5 mm).
- Larger effective cone area: surround design allows a smaller installation diameter and a larger effective cone area than typical 50 mm speakers.
- Push-pull neodymium magnet: higher sensitivity and low distortion.
- Glass-bead reinforced polymer basket: rigid, low ringing, heat resistant and compact.
- FlexMount50 ring included: universal CFM50 MULTI.1 ring for car-specific or universal fitting, plus mounting ring with grille.
Drivers & Construction
- Cone: silicon-coated paper, cone area (Sd) 19.6 cm².
- Dust cap: aluminum, bonded to the voice coil.
- Voice coil: 20 mm diameter, 7 mm winding height.
- Magnet: push-pull neodymium system.
- Basket: polymer composite reinforced with glass beads.
- Surround: specially shaped rubber surround.
Acoustic Performance
- Power handling: 70 W RMS / 100 W max.
- Impedance: 3 Ω (DC resistance 3.1 Ω).
- Sensitivity: 89 dB @ 2.83 V / 1 m; 85 dB @ 1 W / 1 m.
- Frequency response: 300 – 20,000 Hz.
- T/S parameters: Fs 240 Hz, Qms 3.09, Qes 0.80, Qts 0.68, Vas 0.16 l, Cms 300 µm/N, BxL 2.8 Tm, Mms 1.43 g, Rms 0.71 kg/s.
- Excursion: max. linear excursion (Xlin) ±2.5 mm; max. mechanical excursion (Xmax) ±3.5 mm.
Installation Notes
- Dimensions: outer diameter 59.8 mm (2.34″), 70.0 mm (2.75″) with universal mounting ring; installation diameter 50.9 mm (2.00″); installation depth 25.2 mm (0.99″).
- FlexMount50: universal CFM50 MULTI.1 rings included; car-specific rings (e.g. for Audi, Ford, Mercedes) can be found with the FlexMount Finder.
- Included mounting parts: speaker gaskets and mounting rings with grille are supplied.
Technical Specifications
| Power handling RMS / Max. | P |
70 / 100 Watts |
| Impedance | Z | 3 Ω |
| DC resistance | Re | 3.1 Ω |
| Frequency response | 300 Hz – 20,000 Hz | |
| Resonance frequency | Fs | 240 Hz |
| Mechanical Q factor | Qms | 3.09 |
| Electrical Q factor | Qes | 0.80 |
| Total Q factor | Qts | 0.68 |
| Compliance | Cms |
300 µm/N |
| Equivalent air volume | Vas | 0.16 L |
| Force factor | B*I |
2.8 Tm |
| Sensitivity | SPL | 89 dB @ 2.83 V / 1m 85 dB @ 1W / 1m |
| Cone area | Sd | 19.6 cm² |
| Moving mass | Mms | 1.43 g |
| Cone material | Silicon coated paper cone | |
| Mechanical resistance | Rms | 0.71 kg/s |
| Voice coil diameter | ø | 20 mm |
| Voice coil winding height | 7 mm | |
| Max. linear excursion | Xlin | +/- 2.5 mm |
| Max. mechanical excursion | Xmax | +/- 3.5 mm |
| Outer diameter | ø | 59.8 mm / 2.34″ |
| Outer diameter with universal mounting ring | ø | 70.0 mm / 2.75″ |
| Installation diameter | ø | 50.9 mm / 2.00″ |
| Installation depth | 25.2 mm / 0.99″ | |
| Features | Powerful push-pull neodymium magnet system, FlexMount50 |
Scope of Delivery
2 x Ci5 M50FM-S3
2 x Universal FlexMount CFM50 MULTI.1
2 x Speaker gasket
2 x Mounting ring with grille
1 x Mounting material
















