Helix Compose Ci3 C165.2FM-S3 – 6.5″ 3 Ohm Coaxial Speakers

HELIX Ci3 C165.2FM-S3

Overview

A high-performance 2-way coaxial speaker system designed for precise, dynamic, and efficient sound reproduction. The HELIX COMPOSE series blends universal speaker design with easy vehicle-specific adaptability, combining advanced materials and thoughtful engineering for reliable performance in a wide range of vehicles.

Performance highlight

The Ci3 series delivers a premium sound experience with refined engineering and quality materials. Each component is optimized for clear audio, making it a perfect match for HELIX and MATCH amplifiers. Mechanical and connection features are designed for safe installation, long-term durability, and easy integration into existing car audio systems.

High efficiency

The system uses 3 Ohm technology, ensuring better amplifier performance and noticeable sound output with improved energy efficiency.

Cenosphere paper cone

A special “Cenosphere” coating reinforces the cone with lightweight hollow spheres embedded in a polyamide layer. This increases stiffness, reduces unwanted resonance, and improves damping. The result is a stable yet lightweight cone that delivers clear, precise sound reproduction.

High-tech polymer basket

The Ci3 speaker basket is made from a reinforced polymer composite, strengthened with glass particles for durability and minimal self-resonance. This design prevents magnetic interference, withstands temperature changes, and allows for compact installation even in limited spaces.

Detailed highs and stable performance

A 0.75” (20 mm) titanium dome tweeter combines strength, low mass, and high damping for accurate and distortion-free treble. It is designed for high thermal resistance and long-lasting reliability.

FlexMount165 – adaptable installation

The FlexMount system allows universal speakers to be converted into vehicle-specific ones using specially designed adapter rings. This enables perfect fitting into factory locations with improved acoustic alignment and easy, professional installation.

ProConnect terminal

The ProConnect terminal provides a secure and flexible connection option. It supports both standard speaker cables and optional WireKits for a plug-and-play setup. The connector is durable, polarity-protected, and built for mechanical and electrical reliability.

WireKits – simple plug-and-play

Optional WireKits make installation fast and safe by connecting the speaker directly to the vehicle’s original wiring. Built to automotive-grade standards, these cables are designed to withstand daily use and demanding environmental conditions.

Features

• 2-way coaxial speaker system with high-quality sound and versatile installation

• 3 Ohm impedance for efficient amplifier output

• Automotive-grade ProConnect terminal for secure, flexible connection

• Compatible with optional WireKits for plug-and-play setup

Tweeter

• 0.75” / 20 mm titanium dome tweeter for crisp and accurate treble

• Neodymium magnet for efficient magnetic response

Midbass

• 6.5” / 165 mm Cenosphere-coated paper cone for detailed sound reproduction

• Reinforced polymer basket for stability and reduced resonance

• High-performance magnet system for precision and responsiveness

Crossover

• Integrated with 6 dB slope

• Supports optional FlexMount165 adapters for optimal in-car acoustic performance

• Compatible with optional WireKits for non-destructive integration

  Technical data

  Power handling RMS / Max.	P	100 / 150 Watts
  Frequency response		60 Hz – 25,000 Hz
  Impedance	Z	3 Ω
  Sensitivity	SPL	92 dB @ 2.83V / 1m 88 dB @ 1W / 1m
  Outer diameter	ø	165.0 mm / 6.50”
  Installation diameter	ø	142.0 mm / 5.59”
  Installation depth		60.7 mm / 2.39”
  Midbass
  Impedance	Z	3 Ω
  DC resistance	Re	3.1 Ω
  Resonance frequency	Fs	72 Hz
  Mechanical Q factor	Qms	4.02
  Electrical Q factor	Qes	1.04
  Total Q factor	Qts	0.82
  Compliance	Cms	466 μm/N
  Equivalent air volume	Vas	11.5 L
  Force factor	B*l	3.8 Tm
  Cone area	Sd	133 cm2
  Moving mass	Mms	10.4 g
  Mechanical resistance	Rms	1.17 kg/s
  Voice coil diameter	ø	25 mm
  Voice coil winding height		10.5 mm
  Max. linear excursion	Xmax	+/- 3.2 mm
  Tweeter
  Voice coil diameter	ø	20 mm
  Features
  Tweeter		Titanium dome and neodymium magnet
  Midbass		Paper with Cenosphere coating, ProConnect terminal and FlexMount165
  Crossover		Integrated, 6 dB highpass

  Compatibility

  • FlexMount165
  • WireKits