Rockford Fosgate T142 Power 4" 2-Way Full-Range Speaker

4" 2-Way Power Series Coaxial 40W RMS, 86dB, Carbon Fibre & Polypropylene Cone, Aluminium Dome Tweeter, 12dB/Octave Butterworth Crossover.

Product Overview

The Rockford Fosgate Power T142 is a 4" 2-way coaxial speaker rated at 40W RMS (80W peak) a high-performance OEM replacement speaker from Rockford Fosgate's premium Power series. The T142 is engineered for buyers for whom a standard replacement speaker is not sufficient, introducing construction materials from Rockford Fosgate's component speaker range into a coaxial format: a carbon fibre and polypropylene injection-moulded composite cone, a 1" (25mm) aluminium dome tweeter with polyurethane suspension, and a built-in 12dB/octave Butterworth high-pass crossover.

Confirmed specifications include 4-Ohm impedance, 86dB sensitivity, 90Hz to 22kHz frequency response, 46mm (1.79") mounting depth, CEA-2031 compliant power rating, and shipping weight. Adapter plates for both 4"×6" and 6"×8" oval positions are included alongside standard mounting hardware. Grilles are not included.

Key Specifications

• Speaker size: 4.0 inch
• Configuration: 2-way coaxial
• Power handling (RMS): 40W per speaker (CEA-2031 compliant)
• Power handling (peak): 80W per speaker
• Impedance: 4-Ohm
• Sensitivity: 86dB @ 1W/1M
• Frequency response: 90Hz – 22kHz
• Mounting depth: 1.79" (46mm)
• Tweeter: Aluminium dome, 1" (25mm), polyurethane suspension
• Crossover: Built-in HP 12dB/octave Butterworth
• Cone: Carbon fibre and polypropylene injection-moulded composite
• Surround: Butyl rubber
• Basket: FlexFit
• Crossover type: ICC (Integrated Concealed Crossover)
• OEM adapter plates: 4"×6" and 6"×8" pair (both included)
• Mounting hardware: Included
• Grilles: Not included
• Sold as: Pair (2 speakers — confirmed in description)
• CEA-2031 compliant: Yes
• Shipping weight: 3.8 lbs (1.72 kg) per pair
• Cutout diameter: Not specified — confirm with Rockford Fosgate
• Warranty: Not specified — confirm with Rockford Fosgate

Features & Benefits

• Carbon Fibre and Polypropylene Composite Cone — The cone combines carbon fibre with polypropylene in a single injection-moulded composite structure — carbon fibre contributes high stiffness and low mass while polypropylene provides moisture resistance and dimensional stability. The result is a stiffer, lighter cone than standard polypropylene or mineral-filled polypropylene, producing improved midrange accuracy and transient response.
• 1" Aluminium Dome Tweeter with Polyurethane Suspension — An aluminium dome tweeter produces a bright, fast, detailed high-frequency response suited to the T142's Power series positioning. The polyurethane suspension (surround) at the tweeter dome edge provides controlled compliance and damping — contributing to smooth treble reproduction without the harsh resonance peaks that can affect aluminium domes without appropriate suspension.
• 12dB/Octave Butterworth High-Pass Crossover (ICC) — The built-in high-pass crossover operates at 12dB/octave with a Butterworth filter topology — steeper than a simple 6dB/octave first-order crossover. The Butterworth alignment produces a maximally flat passband response through the crossover region, minimising ripple in the frequency response at the crossover point. The ICC integrates this crossover directly into the tweeter assembly.
• 40W RMS CEA-2031 — Confirmed to the industry CEA-2031 standard for sustained power measurements. 80W peak provides dynamic headroom for programme material transients.
• 86dB Sensitivity — At 86dB, the T142 produces good output from standard head unit and low-powered amplifier power levels.
• 90Hz – 22kHz Frequency Response — The 90Hz lower limit reflects the practical output range of a 4" cone. The 22kHz upper limit confirms extended treble coverage from the 1" aluminium dome tweeter.
• 46mm Mounting Depth — Confirmed mounting depth for installation planning in tight OEM door and dash cavities.
• FlexFit Basket with 4"×6" and 6"×8" Adapter Plates — The FlexFit basket accommodates non-standard OEM mounting cavity profiles, and the included 4"×6" and 6"×8" oval adapter plates extend fitment across three speaker position formats from a single kit.
• Butyl Rubber Surround — UV and heat-resistant synthetic rubber surround for long-term reliability in Australian vehicle environments.

Technical Specs

Compatible With / Goes Well With

Suitable installation positions:

• Standard 4" round factory speaker positions
• 4"×6" oval positions (adapter plate included)
• 6"×8" oval positions (adapter plate included)

Pairs well with:

• Rockford Fosgate T400-4, T600-4, or T1000-4AD 4-channel amplifiers
• Dedicated subwoofer system for bass below 90Hz

Weight

1.72 kg per pair (shipping weight)

Frequently Asked Questions

What is the carbon fibre and polypropylene composite cone?

The cone is injection-moulded from a composite of carbon fibre and polypropylene. Carbon fibre contributes high stiffness-to-mass ratio while polypropylene provides moisture resistance and consistent dimensional stability. The composite is stiffer and lighter than standard polypropylene — reducing cone flex under load for more accurate midrange reproduction and improved transient response.

What is the significance of the polyurethane tweeter suspension?

The polyurethane suspension surrounds the edge of the aluminium dome tweeter and provides the compliance mechanism that allows the dome to move while controlling its excursion. Polyurethane provides smooth damping characteristics that help control the resonant behaviour of an aluminium dome — contributing to smooth, detailed treble without the harsh metallic ringing that can occur in aluminium domes without appropriate suspension treatment.

What is a 12dB/octave Butterworth crossover?

A 12dB/octave crossover attenuates the signal by 12dB for every doubling of frequency beyond the crossover point — a steeper roll-off than a first-order 6dB/octave design. The Butterworth topology produces a maximally flat frequency response through the crossover region, minimising ripple or peaks at the transition between the woofer and tweeter. This crossover type is a step up from the simpler designs used in basic coaxial speakers.

What adapter plates are included with the T142?

Both a 4"×6" and a 6"×8" adapter plate pair are included — extending the T142's fitment range from the standard 4" round position to these two oval formats as well.

Are grilles included with the T142?

No — grilles are not included. The kit contains two speakers, two adapter plates (4"×6" and 6"×8"), and mounting hardware only.