Helix Ci3 K100.2FM-S3 MK2 – 4″ / 100 mm 2-way component system, 3 Ω
The Ci3 K100.2FM-S3 MK2 is a 2-way component set from the COMPOSE i3 series of the HELIX COMPOSE platform, which is designed to suit vehicle installation while retaining the performance of universal speakers. It pairs the Ci3 M100FM-S3 100 mm midrange with the Ci3 T20FM-AL MK2 20 mm tweeter and a dedicated Ci3 FX-UNI.2 crossover per side. Its 3 Ω design works efficiently with HELIX and MATCH amplifiers.
The midrange uses a Cenosphere-coated paper cone in a glass-bead reinforced polymer basket with a shallow neodymium magnet, while the tweeter combines a black aluminium dome with a neodymium magnet for detailed highs. The compact separate crossover offers a six-step tweeter level adjustment and tweeter protection, COMPOSE Connect plug connectors prevent polarity mistakes, and both drivers are prepared for car-specific FlexMount20 / FlexMount100 adaptors.
Key Features
- Complete 2-way kit: 100 mm midrange, 20 mm tweeter and separate crossovers with versatile mounting options
- 3 Ω technology: high efficiency for maximum amplifier output with HELIX and MATCH amplifiers
- Aluminium dome tweeter: 20 mm black aluminium dome with neodymium magnet in a compact housing
- Tweeter pods included: flush-mount and angle-mount pods for several mounting options
- Cenosphere-coated midrange cone: hollow spheres in a polyamide layer for stiffness and damping
- Shallow neodymium midrange magnet: keeps midrange installation depth to 30 mm
- Glass-bead reinforced polymer basket: rigid, low-resonance and heat-resistant midrange basket
- Separate compact crossover: Ci3 FX-UNI.2 with 12 dB tweeter high-pass, tweeter protection and six-step level adjustment
- COMPOSE Connect & FlexConnect: automotive-grade plug connectors that prevent polarity reversal
- Klippel-verified development: driver development verified with the Klippel Analyzer System
- FlexMount20 / FlexMount100 ready: designed for car-specific adaptors for installation in original mounting locations
- WireKit compatible: crossover compatible with WireKits for connection to the factory harness
Drivers & Construction
- Included drivers: 2 × Ci3 T20FM-AL MK2 tweeter, 2 × Ci3 M100FM-S3 midrange, 2 × Ci3 FX-UNI.2 crossover
- Tweeter: black aluminium dome, neodymium magnet, 20 mm voice coil, compact housing, FlexMount20
- Midrange: paper cone with Cenosphere coating, polyurethane dust cap, 25 mm voice coil (4.8 mm winding height), neodymium magnet, glass-bead reinforced polymer basket, FlexConnect terminal, FlexMount100
- Also in the box: 2 × connection cable, 2 × COMPOSE Connector Kit, 2 × tweeter mounting accessory set, 2 × midrange mounting material, 2 × FlexConnect inlay A, 1 × mounting material
Acoustic Performance
- Power handling: 80 W RMS / 120 W max
- System impedance: 3 Ω (midrange 3 Ω / Re 3.0 Ω; tweeter 4 Ω)
- Sensitivity: 91 dB @ 2.83 V / 1 m; 87 dB @ 1 W / 1 m
- Frequency response: 120 Hz – 25,000 Hz
- Midrange Thiele/Small: Fs 146 Hz, Qms 4.49, Qes 1.02, Qts 0.83, Vas 1.1 l, Cms 280 µm/N, Bl 3.4 Tm, Sd 53 cm², Mms 4.3 g, Rms 0.87 kg/s, Xmax ±2.0 mm
- Tweeter resonance (Fs): 1,800 Hz
Crossover
- Type: separate, compact Ci3 FX-UNI.2 passive crossover (one per side)
- Tweeter slope: 12 dB high-pass
- Tweeter protection: integrated
- Level adjustment: tweeter level adjustable in six steps
- Dimensions: 103.3 × 50.4 × 25.0 mm / 4.07 × 1.98 × 0.98″
- Connection: COMPOSE Connect plug connectors; compatible with WireKits
Installation Notes
- Tweeter: outer diameter 32.0 mm / 1.26″, installation depth 9.8 mm / 0.39″; flush-mount or angle-mount with the included pods, or FlexMount20 adaptors
- Midrange: outer diameter 98.0 mm / 3.86″, installation diameter 89.0 mm / 3.50″, installation depth 30.0 mm / 1.18″
- Accessories named: CFMK20 BMW.1, TES.1, TES.2, POR.1, MB.1; CFMK100 BMW.1, BMW.2, TES.1, MB.1, JLR.1, VOL.1; FlexConnect inlays; WireKit CWK BMW.FX-550CC
Technical Specifications
| Power handling RMS / Max. | P | 80 / 120 Watts |
| Frequency response | 120 Hz – 25,000 Hz | |
| Impedance | Z | 3 Ω |
| Sensitivity | SPL | 91 dB @ 2.83V / 1m 87 dB @ 1W / 1m |
| Outer diameter | ø |
Tweeter: 32.0 mm / 1.26” |
| Installation diameter | ø |
Tweeter: 32.0 mm / 1.26” |
| Installation depth |
Tweeter: 9.8 mm / 0.39” |
|
| Dimensions crossover |
103.3 x 50.4 x 25.0 mm / |
|
| Midrange | ||
| Impedance | Z | 3 Ω |
| DC resistance | Re | 3.0 Ω |
| Resonance frequency | Fs | 146 Hz |
| Mechanical Q factor | Qms | 4.49 |
| Electrical Q factor | Qes | 1.02 |
| Total Q factor | Qts | 0.83 |
| Compliance | Cms | 280 μm/N |
| Equivalent air volume | Vas | 1.1 L |
| Force factor | B*l | 3.4 Tm |
| Cone area | Sd | 53 cm2 |
| Moving mass | Mms | 4.3 g |
| Mechanical resistance | Rms | 0.87 kg/s |
| Voice coil diameter | ø | 25 mm |
|
Voice coil winding height |
4.8 mm | |
| Max. linear excursion | Xmax | +/- 2.0 mm |
| Tweeter | ||
| Impedance | Z | 4 Ω |
| Resonance frequency | Fs | 1800 Hz |
| Voice coil diameter | ø | 20 mm |
| Features | ||
| Tweeter |
Ultra compact, aluminum dome, neodymium magnet and FlexMount20 |
|
| Midrange |
Paper with Cenosphere coating, FlexConnect terminal, neodymium magnet and FlexMount100 |
|
| Crossover |
Tweeter: 12 dB highpass, protection and level adjustment |
Scope of Delivery
2 x Tweeter Ci3 T20FM-AL MK2
2 x Midrange Ci3 M100FM-S3
2 x Crossover Ci3 FX-UNI.2
2 x Connection cable
2 x COMPOSE Connector Kit
2 x Tweeter mounting accessories
2 x Midrange mounting material
2 x FlexConnect inlay A
1 x Mounting material














