Helix Compose i5 Ci5 T25FM-CA Tweeters 1 Inch 25mm FlexMount Aluminum Dome
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The Helix Compose i5 Ci5 T25FM-CA is a pair of 1-inch (25 mm) ceramic-coated aluminium dome tweeters with FlexMount25 compatibility, part of the Helix Compose i5 component speaker platform.
Key specifications
- Size: 1 inch / 25 mm tweeter, sold as a pair
- Dome: ceramic-coated aluminium; neodymium magnet
- Impedance: 4 ohms (DC resistance 3.2 ohms)
- Frequency response: 2,000 Hz – 25,000 Hz
- Sensitivity: 94.0 dB at 2.83V/1m; 91.0 dB at 1W/1m
- Installation diameter: 38 mm; installation depth: 11.7 mm; outer diameter: 40 mm
- Recommended high-pass: above 4,000 Hz (6 dB/oct), above 3,000 Hz (12 dB/oct), above 2,500 Hz (24 dB/oct)
- Includes flush and angle mounting pods
- Compatible with car-specific FlexMount25 adaptors and WireKits (optional)
Helix Compose: universal speakers evolved
The Helix Compose platform was built to bridge the gap between universal and vehicle-specific speaker systems. The result combines high efficiency, strong dynamics and quality sound in a format that fits a wide range of vehicles. All i5 series speaker impedances are matched for use with Helix and MATCH amplifiers.
The sound sensation for sophisticated music lovers
The Helix Compose i5 series sits between the i7 and i3 ranges, aimed at listeners who want a genuine hi-fi upgrade. It pairs strong sound quality with practical installation, and all impedances are matched for use with Helix and MATCH amplifiers. The Ci5 T25FM-CA works as part of a wider Compose i5 system — the range also includes the Ci5 M80FM-S3 3-inch midrange and the Ci5 S200FM-S2 8-inch subwoofer for a complete build.
Brilliant treble with excellent dispersion characteristics
Despite its 25 mm / 1-inch diameter, the Ci5 T25FM-CA delivers wide dispersion and a strong off-axis response — useful for OEM installation positions. The ceramic-coated aluminium dome provides a balanced frequency response and clean decay characteristics for clear, realistic high-frequency reproduction. A sturdy aluminium housing with integrated grille protects the dome, while the high-efficiency neodymium magnet ensures linear magnetic flow. Compact dimensions and the supplied mounting pods — flush and angled — give installers flexible placement options.
FlexMount25: universal meets car-specific
FlexMount is a mounting system using specially developed adaptor rings, allowing Compose FlexMount speakers to be installed in a wide range of vehicles. With the matching FlexMount25 adaptor ring, the Ci5 T25FM-CA can drop into a vehicle's original tweeter location in an acoustically optimised way.
WireKits: plug and play at its best
Helix WireKits connect Helix Compose components to the vehicle's original wiring harness, or optionally to a crossover. Built to automotive industry standards, these lockable adaptor cables are designed to handle the demanding conditions installers encounter daily.
Explore the full range in Helix Compose i5.
Specification
| Impedance | Z 4 Ω |
|---|---|
| Frequency response | 2,000 Hz - 25,000 Hz |
| Sensitivity | SPL 94.0 dB @ 2.83V / 1m 91.0 dB @ 1W / 1m |
| Voice coil | diameter Ø 25 mm |
| Cone | material Aluminum with ceramic coating |
More specs
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What's Included
- 2 x Ci5 T25FM-CA
- 2 x Tweeter flush mount
- 2 x Tweeter pod
- 2 x Mounting material
- 1 x Instruction manual
Helix
About the Helix CI21002
From our tech experts at CEN
The Helix Ci5 T25FM-CA is a pair of 1 inch (25 mm) ceramic-coated aluminium dome tweeters from the Compose i5 series, with neodymium magnets. They cover 2 to 25 kHz at 4 ohms with 94 dB sensitivity, and need only 11.7 mm of installation depth.
Who it suits
Drivers building an i5 front stage, or upgrading factory tweeters where a car-specific FlexMount25 adaptor is available. Flush and angled mounting pods are included for custom positions. The Ci5 M80FM-S3 midrange makes a good partner in a three-way build.
Our tech experts advise
Helix recommends a high-pass above 4 kHz at 6 dB per octave, above 3 kHz at 12 dB, or above 2.5 kHz at 24 dB. Use a DSP or suitable crossover and never run them full range. Aim them towards the listening position. Get in touch.
Explore the full Helix range at CEN, with fast UK dispatch and expert advice from our Nottingham team. Shop all Helix
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Have it Fitted By Our Team
Our team fits car audio, stereos, dash cams and vehicle security at our workshop in Beeston, Nottingham. Tell us your vehicle and we'll confirm the parts and a fitted price.
- 1
Tell us your vehicle
Make, model and year, and what you'd like fitted.
- 2
We confirm the parts
Fascia, wiring and interfaces checked for your car, with a fitted price.
- 3
Fitted at our workshop
Bring it to our Beeston workshop and we do the rest.
Unit 25 Technology Drive, Beeston, Nottingham NG9 1LA
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Frequently Asked Questions
Q: Will these speakers fit my car?
A: Most car speakers are standard sizes, but mounting depth and fitting rings vary by vehicle. Check the size in the Specification tab against your vehicle, or contact CEN with your registration and we will confirm fitment and any adapters or fitting kits you need.
Q: Do I need an amplifier to run these speakers?
A: Not always. Most speakers will run from a standard head unit, but a dedicated amplifier lets them perform at their best, particularly for component sets and higher power handling models. The RMS figure in the Specification tab is the guide to how much clean power they can use.
Q: What is the difference between coaxial and component speakers?
A: Coaxial speakers combine the tweeter and woofer in one unit for a simple like-for-like upgrade. Component sets separate the tweeter and woofer with a crossover for better imaging and detail, and suit installs where sound quality is the priority.
Q: Do these come as a pair?
A: Unless stated otherwise, car speakers are sold in pairs. Check the product title and What's Included tab, which lists exactly what is in the box.
Q: Can CEN fit these speakers for me?
A: Yes. CEN offers professional installation from our Nottingham premises. Contact us to book an installation slot or ask for a fitting quote.
Q: Can the HELIX Ci5 T25FM-CA fit in my car's original tweeter location?
A: Yes, with the optional car-specific FlexMount25 adaptor ring for your vehicle, which allows acoustically optimised installation in the original mounting position. Optional WireKits connect them to the original wiring harness.
Q: What crossover frequency should I use with the Ci5 T25FM-CA?
A: HELIX recommends a high-pass above 4,000Hz at 6dB/octave, above 3,000Hz at 12dB/octave or above 2,500Hz at 24dB/octave.
Q: What mounting options are included with the Ci5 T25FM-CA?
A: The box contains two tweeters, two flush mounts, two tweeter pods, mounting material for both and an instruction manual.
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