Helix Ci7 T20FM-SC Installer-Package – 20 mm high-end silk-dome tweeter with coupling volume
The Ci7 T20FM-SC is the tweeter of the HELIX COMPOSE i7 series, the high-end line of the COMPOSE platform. It is manufactured in Germany and its development was influenced by the sister brand BRAX. COMPOSE takes proven universal speakers and re-engineers them for modern vehicles, following the idea of being developed inside the vehicle, for the vehicle, so that one universal driver can be installed in a car-specific way.
Installer Package – Scope of Delivery
This multi-unit installer package is aimed at professional installers and workshops who fit the same model in several vehicles. The package contains:
- 10 x High-end tweeter HELIX Ci7 T20FM-SC
The 20 mm dome is a fine-mesh silk fabric coated on both sides with a viscoelastic material (Acronal). Together with lamb’s wool damping and an integrated, damped coupling volume this lowers the resonance frequency to 950 Hz and allows comparatively low crossover points. The impedance is matched to HELIX and MATCH amplifiers, and FlexMount20 adaptor rings plus WireKits make plug-and-play installation in original tweeter locations possible.
Key Features
- Wide dispersion: the small 20 mm silk dome spreads high frequencies very evenly across the cabin.
- Coupling volume: an integrated, damped rear volume lowers the resonance frequency and permits a low crossover frequency.
- Lightweight silk dome: fine-mesh silk with viscoelastic coating for smooth yet brilliant treble.
- Neodymium magnet: high-efficiency magnet for linear magnetic flux.
- Solid aluminium housing: the tweeter body is machined from solid aluminium.
- Compact design: small dimensions with several mounting options.
- Mounting pods: pods for flush and angled mounting are part of the concept.
- FlexMount20 compatible: optional car-specific adaptors for original mounting positions.
- WireKits compatible: optional automotive-grade adaptor cables for non-destructive connection to the factory harness or to a crossover.
- Amplifier matching: impedance tuned for HELIX and MATCH amplifiers.
- Made in Germany.
Drivers & Construction
20 mm silk dome with coupling volume and a 20 mm voice coil, neodymium magnet system and a housing turned from solid aluminium. Outer diameter is 32 mm (1.26″).
Acoustic Performance
Nominal impedance 4 Ω (DC resistance 3.4 Ω), frequency response 1,500–30,000 Hz, resonance frequency 950 Hz, sensitivity 91.0 dB at 2.83 V/1 m (88.0 dB at 1 W/1 m).
Crossover
Recommended minimum high-pass frequencies: above 4,000 Hz with 6 dB/octave, above 3,000 Hz with 12 dB/octave and above 2,500 Hz with 24 dB/octave slopes.
Installation Notes
Installation diameter 27.2 mm (1.07″), installation depth 19 mm (0.75″). For factory locations use the vehicle-specific FlexMount20 adaptors; connection to the original wiring is possible with the optional WireKits.
Technical Specifications
| Impedance | Z | 4 Ω |
| DC resistance | Re | 3.4 Ω |
| Frequency response | 1,500 Hz – 30,000 Hz | |
| Resonance frequency | Fs | 950 Hz |
| Sensitivity | SPL | 91.0 dB @ 2.83V / 1m 88.0 dB @ 1W / 1m |
| Voice coil diameter | Ø | 20 mm |
| Cone material | Silk dome with coupling volume | |
| Outer diameter | 32 mm / 1.26″ | |
| Installation diameter | 27.2 mm / 1.07″ | |
| Installation depth | 19 mm / 0.75″ | |
| Recommended crossover frequencies for the highpass | ||
| Slope | Minimum crossover frequency | |
| 6 dB/Octave | > 4,000 Hz | |
| 12 dB/Octave | > 3,000 Hz | |
| 24 dB/Octave | > 2,500 Hz |
Scope of Delivery
10 x High-end tweeter Ci7 T20FM-SC
