Our take on the Infinity Reference X REF-4002cfx

by John Pollard

Designed for more clarity
Do you want to hear the details you've been missing in your car's sound system? You'll enjoy exceptional clarity from Infinity's Reference X Series REF-4002cfx 4" speakers. Infinity uses textile dome tweeters to give you amazing levels of detail without sounding harsh; each tweeter features a level control switch so you can boost the brightness to your taste.

Larger woofer for more bass
The REF-4002cfx features tough polypropylene woofers and durable hi-roll rubber surrounds that deliver strong performance. Each Plus One+ woofer sports a significantly larger cone than speakers of similar size, adding plenty of punch to the speaker's smooth and accurate highs.

Great for any power supply
You can power these speakers with up to 35 watts of RMS power — they'll work great with an external amplifier, but they're also sensitive enough to be a good match for a factory or aftermarket stereo. Plus, Infinity comes up with a safe way to get a little more power out of your system — these 3-ohm speakers combine with the speaker wire in your car so your car stereo sees actual 4-ohm impedance. Grilles are not included — factory grilles are appropriate for most installations.

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Highlights:

4" 2-way speakers (pair)
Plus One+ Injection-Molded Polypropylene (IMPP) woofer cone with hi-roll rubber surround
1" edge-driven textile dome tweeter
True Four Ohm Impedance technology: speaker's 3-ohm impedance combines with speaker wire impedance for a 4-ohm load
compatible with virtually all factory or aftermarket car stereos
power range: 5-35 watts RMS (105 watts peak power)
frequency response: 75-21,000 Hz
sensitivity: 92 dB
top-mount depth: 1-7/8"
warranty: 1 year
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Hands-on research from the Crutchfield Labs (what are the Labs?)

Features and specs chart | What’s in the box? | In-depth notes

Features and Specs

General
Design Loading...	2-way
Tweeter Design Loading...	Edge-Driven Dome
Tweeter Composition Loading...	Textile
Woofer Composition Loading...	Polypropylene
Woofer Surround Loading...	Rubber
Parts Warranty Loading...	1 Year
Labor Warranty Loading...	1 Year
Specifications
Sensitivity Loading...	92 dB at 2.83 volts
Frequency Response Loading...	75 - 21k Hz
RMS Power Range (Watts) Loading...	5-35
Peak Power Handling (Watts) Loading...	105
Impedance (Ohms) Loading...	3
Top-mount Depth (Inches) Loading...	1 7/8
Bottom-mount Depth (Inches) Loading...	N/A
Cutout Diameter or Length (inches) Loading...	3 11/16

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What's in the box?

Download owner's manual

Two 2-way speakers
2 Adhesive backed foam gaskets
2 Infinity logos
Template on box
Owner's manual (English/ Danish/ German/ Spanish/ Finnish/ French/ Italian/ Dutch/ Polish/ Portuguese/ Russian/ Swedish/ Turkish/ Chinese)

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Features

Plus One+ Woofer Cones: Each speaker uses a cone significantly larger than other speakers of the same size. This is accomplished by using a unique basket design and hi-roll surround. The Plus One+ design offers greater bass output and an increase in efficiency.

Hi-roll Rubber Surrounds: The hi-roll rubber surrounds allow the woofers a greater range of movement, resulting in longer X-max and more bass output.

Textile Dome Tweeters: Each speaker uses an edge-driven textile dome tweeter for smooth, accurate highs. A switch on the housing allows you to adjust the tweeter output; choose 0 dB or +3dB, useful if the speakers are mounted low in a door where high frequencies are easily absorbed.

True Four Ohm Impedance Technology: The speaker's 3-ohm impedance combined with the impedance of your speaker wire provides a true 4-ohm load to your connected head unit or amplifier.

Power Handling: Although Infinity rates the 4002cfx speakers at 35 watts RMS (continuous average), they also recommend amplifiers with a power rating from 5 to 50 watts RMS.