The Real Cable FL400B embodies the perfect blend of acoustic performance and ease of installation. This ultra-flat 4 mm² cable stands out as a benchmark in its category, offering an elegant solution for those who refuse to sacrifice sound quality for the sake of discretion.
A product of Real Cable’s French expertise, this model features exceptionally pure OFC copper and innovative braiding that optimizes signal transmission while ensuring an almost invisible installation.
The OFC (Oxygen Free Copper) used in the FL400B boasts a purity of 99.99%, placing this cable among high-performance conductors. This advanced deoxygenation process eliminates oxygen impurities that could form micro-bubbles and alter the metal’s electrical properties.
The difference compared to standard copper is evident in terms of resistivity and longevity. OFC copper maintains its conductive properties over time, offering better resistance to oxidation, which could otherwise gradually degrade transmission quality. This stability ensures consistent performance for many years.
The crystalline structure of OFC copper, more homogeneous than that of conventional industrial copper, allows for a smoother flow of electrons. This results in a more transparent sound reproduction, particularly noticeable in the rendering of details and the definition of the stereo image.
The FL400B’s major innovation lies in its specific flat braiding, designed to reduce linear capacitance. This electrical property, often overlooked, plays a crucial role in transmission quality, especially over long distances.
Linear capacitance refers to the electrical capacitance per unit length between the two conductors of a cable. High capacitance can filter out high frequencies and alter the signal’s phase, affecting the timing accuracy of sound reproduction. The FL400B’s flat braiding minimizes this parasitic capacitance by optimizing the geometry of the conductors.
This technical design translates into better preservation of fast transients and micro-details. Percussive instrument attacks retain their precision, and spatialization benefits from enhanced definition. The effect is particularly noticeable in the mid-high registers, where clarity and definition are significantly improved.
The FL400B’s ultra-flat profile revolutionizes the approach to hi-fi and home theater installation. Unlike traditional round cables, its geometry allows for discreet routing under carpets, along baseboards, or even beneath certain thin wall coverings.
This ease of installation solves the eternal dilemma between acoustic performance and home aesthetics. 5.1 or 7.1 home theater systems, traditionally complex to wire invisibly, find in the FL400B an elegant solution for powering surround speakers without compromising room design.
The sheath’s flexibility makes it easy to run the cable around corners and change direction. The cable hugs the contours of baseboards perfectly and can even pass under doors, where a round cable would create a visible obstruction. This adaptability greatly reduces installation time and limits the need for drilling or wall chasing.
The FL400B delivers a balanced and defined sound, characteristic of Real Cable’s sonic philosophy. The bass is firm and controlled, with no muddiness or lag. This precision in the low end contributes to the overall clarity of the spectrum and prevents frequency masking.
In the midrange, the cable preserves the naturalness of voices and acoustic instruments. Timbres retain their authenticity, without artificial coloration. This neutrality allows the FL400B to adapt to different types of music and systems, from acoustic jazz to contemporary electronic.
The highs, described as “luminous” by users, gain presence without becoming aggressive. This quality is a direct result of the OFC copper and optimized braiding, which preserve the integrity of high frequencies. Cymbals regain their natural metallic brilliance, and the harmonics of string instruments unfold with finesse.
The FL400B’s 4 mm² cross-section is primarily intended for systems delivering between 80 and 250 watts per channel. This power range covers the majority of home hi-fi and home theater setups, from bookshelf systems to demanding audiophile configurations.
For multi-channel home theater installations, the FL400B excels in wiring surround and rear speakers. Its discreet profile makes it easy to run cables through the living room without compromising aesthetics. Professional installers frequently choose it for this reason, especially in high-end projects where technical invisibility must serve the art of living.
In stereo hi-fi, the cable is perfectly suited to integrated amplifiers and medium- to high-power amplifiers. Its sonic neutrality respects the musical signature of the associated electronics, whether tube or transistor amplification. This versatility is a valuable asset for audiophiles who regularly upgrade their systems.
Absolutely. The FL400B’s 4 mm² cross-section is specifically designed for amplifiers delivering between 80 and 250 watts per channel. A 150-watt amplifier falls within the optimal usage range, ensuring lossless transmission and faithful reproduction of the full musical dynamic. The cable’s low linear resistance preserves the amplifier’s damping of the speakers.
The FL400B’s flat braiding, designed to reduce linear capacitance, optimizes performance over long distances. Up to 15–20 meters, signal degradation remains negligible thanks to the 4 mm² cross-section and the quality of the OFC copper. Beyond that, as with any cable, a slight attenuation of the highs may occur, but it remains far less than with a cable of smaller cross-section or lower quality.
Absolutely. The FL400B’s 99.99% oxygen-free copper has lower resistivity and greater long-term stability than standard industrial copper. This difference results in better preservation of sound details, more precise spatialization, and increased durability. The investment is all the more justified as Real Cable offers a lifetime warranty on its cables, offsetting the initial extra cost over several decades.
No, the FL400B does not have any particular directionality. The two conductors are perfectly symmetrical and can be connected interchangeably to the positive and negative terminals. You simply need to maintain phase consistency between the two speakers of the same stereo channel, using the same conductor (identifiable by marking or shape) for all positive terminals.
Like most quality cables, the FL400B can benefit from a brief break-in period to allow the materials to stabilize. Around fifty hours of listening is generally sufficient for the cable to fully reveal its qualities. This phenomenon, related to the relaxation of internal mechanical stresses and surface oxidation of the conductors, remains subtle and does not affect the immediate use of the product.
Eric
Satisfied with the cable quality, but be aware that the cable is quite thick.
Comment from September 19, 2024 — Experience from September 08, 2024
Thierry
Perfect for wiring rear speakers. (40 meters of cabling!) I didn't replace the old cables; I did bi-wiring, just like with my front speakers. The effect is amazing; on SACDs, I really get the same sound as on the fronts.
Very practical to hide flat on the floor, but it's tricky to go around windows and stick the cable to the walls because you can't bend it. The solution is to separate the two cables with a cutter for a few centimeters to make a sort of loop.
It would be helpful to show a photo to illustrate my point.
Comment from July 05, 2024 — Experience from June 24, 2024
Philippe
Very good. No issues. High quality.
Comment from March 07, 2022 — Experience from December 20, 2021
