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Speaker cable


Manufacturer: FOILFLEX
Price (in Poland): 1200 USD



Provided for test by: FOILFLEX

CABLES: 1. «a thick line made of a strain of insulated metal wires» | CHORD: 1. «an element of an electrical circuit connecting power source with a receiver» | WIRE: 1. «a thin, flexible, metal rod», 2. common. «telegraph or telephone wire» (Polish Language Dictionary PWN, accessed: 26.02.2020).

have a task for you - please close your eyes and quickly imagine: a CABLE. What do you see You will probably see different types of cables, power one or computer one, and finally some kind of interconnect. So they will have different functions and purpose. But I'm sure almost everyone will see the ROUND cable in their minds. Which will be perfectly normal - most cables had and still have just such a cross-section. This results directly from used production technologies, based on drawing metal through increasingly smaller "holes" of circular cross-section until the desired diameter is reached. Such wires are then bundled around a common core, wrapped around each other, etc. - usually the ultimate form is a circle.

There are, however, other ways. A wire in the cable does not have to be round at all, it can have an oval or rectangular cross-section. As an example of the former let me remind you of the Acoustic Revive series designated as "(1.8x1.4)" (RCA-1.0 Triple C-FM 1.8x1.4), and of the latter cables from the Mexcel series, from another Japanese manufacturer, Acrolink (e.g. Mexcel 7N-PC9500). But even they have a structure that externally adopts a round shape and is made of 'wires'.

Ribbon | Even more rare are cables that are not round. The most spectacular examples of these are ribbon-shaped cables (also called: "multi-wire planar cables"). Their design is based on wires or ribbons. In the former, many wires are stacked side by side to form a flat ribbon. We all know them - they appear in all computers and other modern electrical devices. This type of cable was invented in 1956 by Cicoil Corporation, a company based in Chatsworth, California (USA).

In the perfectionist audio we deal with, they have also been known for years despite the fact that in analog connections this is not a recommended way of signal transmission. Around 1980, the US Federal Communications Commission discovered that cables of this type act as highly effective antennas, catching electromagnetic interference from the environment. The result of these tests were recommendations to limit the band connections outside the devices, and if they are used occurs, the cables should be grounded.


However, the audio world is governed by its own laws. That is why we know this type of cable, in the form of flat, wide ribbons, with the most spectacular examples coming from Nordost. Wireworld Cable Technology has its kind of "ribbons", and smaller companies worth mentioning are the Polish producer Divine Acoustics and German Ramses-II. Why do they use this type of design? Because it offers certain benefits.

Each cable can be treated as a so-called "black box", characterized by three basic parameters: resistance (R), impedance (L) and capacity (C). In fact, it’s about their counterparts for alternating current, but for the sake of clarity, we are talking about the RLC system. Each change in one of these parameters implies a change in the others. For example, by increasing the impedance we are reducing the capacity, etc. What's more, each such change involves a change in sound.

And that's a feature of ribbon cables - they are high impedance and low capacity cables. Therefore, they create a completely different electrical load for the amplifier. Historically, they were even used as part of the power amplifiers’ output stages, instead of the Zobel Network ("Boucherot Cell"). This is how Naim and Linn designed their amplifiers at some point. With time, they abandoned this idea.

So when I see the ribbon cable I know it is a result of thinking beyond standard calculations. It is difficult to calculate correctly, and even more difficult to manufacture. Both technical and practical knowledge from numerous listening sessions must be applied to properly design it. The mail from Mike Lenehan, the owner of the Australian company FoilFlex (as well as LenehanAudio), therefore, found a fertile ground. As he wrote then, he is not only involved in the production of loudspeakers, as he also manufactures Rob Woodland's Curious USB cables, and he also has his own cable lines - RCA and XLR interconnects and speaker cables. And these are ribbon cables ("Foil Ribbon Cables").

Owner, designer

It all began in the '70s, when my brother and I went to the store and heard a pair of JBL L55 Jubal speakers, powered by an integrated Sonab amplifier with a Sonab turntable! WHAT? - We looked at each other and from that moment on we were both hooked to the high quality sound.

LenehanAudio | We remained passionate amateurs until 1995, when we founded LenehanAudio, which became a full-time job for us, as we were designing loudspeakers and cables. I think we were a little different since we didn't build a sales base in the form of retail outlets. Our main goal was to sell to other audiophile freaks, which is why - rather prematurely - we decided to sell directly.

FoilFlex | In 2011, we founded the FoilFlex, at first as the RibbonTek, and the first cable received the Giant Killers award from the portal. From that moment, after almost 500 hours of research and development with the participation of three designers and several dozen listeners, FoilFlex was born. The current, latest generation of these cables has been on the market for two years.

Design | When you pass voltage or current through a cable, you also cause it to vibrate. The specific length of a symmetrical cable has its main resonance at a certain dominant frequency. And we know what you’re going to say: this frequency can become the dominant, identifiable signature of this cable! And that's not good.

Another analogy that comes to mind is a guitar string, which is intentionally tuned to a specific, dominant frequency or note. The point is, we don't want our cables to create music or add their own sound to the mix, as a guitar does. We just want the cables to transmit an unchanged information about what was sent to them. FoilFlex therefore uses deliberate "de-tuning" of the material structure to eliminate this ringing. Thanks to our technology, we design precise and transparent sounding cables.

We believe that for all analog audio cables, the only medium for signal transmission should be copper! We don't like silver, which always seems to have some sonic signature, which we were just unable to eliminate from the sound.

But we are also a producer of interesting USB cables for Rob Woodland, in which we use silver (it is about the Curious USB - ed.). But it's a digital cable that requires a completely different approach. We do not specialize in digital cables, because it is definitely another specialized field. And yet, the Curious sounds extremely neutral and musical.

Ribbon or Foil cables are simply a necessity, because you can almost completely eliminate the skin effect in this type of design. However, the design of the foil one uses for them is a decisive factor because of its thickness and width. The most modern ribbon (foil) cable differs from countless lesser quality products by the ability to control DCR, inductance and capacity.


FoilFlex cables are designed by Mike Lenehan’s company and do not copy other solutions. The company has been developing the design for more than two years and even just before the original date of sending them to me for testing, they found something that could still have been improved - so shipping was delayed by another month. The cables are made by hand, and yet their price is surprisingly low. A 2.5 m loudspeaker cable terminated with bananas on one side and a spades on the other, will cost you 1,200 US dollars (plus customs fees etc.), and another 450 and 530 USD for RCA and XLR interconnects, respectively.

The speaker cables we are talking about are two tapes 50 mm wide and about 2 mm thick each, fastened together with a wide heat-shrink tubing with the company logo. The cables are directional and, as we read in the short manual, should be connected to the amplifier and loudspeakers in such a way that the inscription on the outer sleeve is directed towards the latter. The ribbons can be terminated with copper spades or bananas and one can order any custom length. The company sells their products directly, with a 30-day guaranteed money back period (the sender bears the shipping costs).

The cables were made of specially prepared C10100 copper foil with a purity of 99.99%, having a width of 48 mm (plus 2 mm for a dielectric); in interconnects, the foil is 19 mm wide. Mike says that the most important design element turned out to be the thickness of the foil, because in this way a balance between resistance and skin effect is established (another, after the RLC, principle of cable design). As he wrote in the email: "by changing the thickness of the foil between 50 and 200 microns you can significantly change the sound".

FoilFlex speaker cables and interconnects feature the same foil, but differ in its thickness and cutting method. They are shielded with special varnish, and on the outside they feature a protective PVC mesh. According to Mike, even the varnish used for insulation changes the sound and - as he says - "dramatically."

While working on prototypes, every type of varnish, as well as a change in its thickness, changed the sound "almost incredibly". The final formula was based on 21 prototypes, with the organic varnish thickness being subsequently reduced.

Cables can be ordered terminated with either spades or with bananas or - as in the case of the review pair - with bananas on one side and spades on the other. Spades and bananas are made of pure copper and are not coated with anything - neither silver, gold nor rhodium. In this way, the cable is entirely made of copper and one could consider replacing the sockets in the amplifier and the speakers with copper ones, at least if one would like to maintain a consistent signal path.


The FoilFlex speaker cable was tested in the "High Fidelity" reference system, connecting the Soulution 710 power amplifier and Harbeth M40.1 speakers; the Soulution is a solid-state amplifier with a high damping factor. The speakers were connected in parallel with the SPEC "Real-Sound Processor" RSP-AZ9EX. I listened to 2 minutes long music pieces, and the tested cable was compared to the Siltech Triple Crown cable in A/B/A mode, with the A and B known.

Recordings used for the test (a selec- tion)

  • The TBM Sounds!, Lasting Impression Music LIM UHD 048LE, „Limited Edition”, CD (2010)
  • Bill Evans Trio, Portrait in Jazz, Riverside/Fantasy RISA-1162-6, SACD/CD (1959/2003)
  • Dave Grusin, Discovered Again! Plus, Sheffield Lab/Lasting Impression Music LIM XR 002, XRCD24 (1976/2003)
  • King Crimson, In The Court of the King Crimson (An Observation by King Crimson). 50th Anniversary Box Set, Atlantic/WOWOW Entertainment [Japan] IEZP-128, „2019 Remix by Steven Wilson”, 3 x HQCD + BD Audio (1969/2019)
  • OST, Gladiator, muz. Hans Zimmer and Lisa Gerrard, Decca Records | Universal Music Polska 467 094-2, CD (2000)
  • Vangelis, Blade Runner, Atlantic Records/Audio Fidelity AFZ 154, „Limited Edition | No. 2398”, SACD/CD (1998/2013)

Each case is different - some reviewed products reveal their secrets slowly, others at once. And it has nothing to do with their final assessment - neither those that are open to the user, like barn doors are, in principle, better or worse, nor those that require concentration and reflection are worse. There is no rule here. FoilFlex speaker cables are completely unique in this context. On the one hand, you can immediately hear what they bring to the sound, how they modify it (because every element in the signal track modifies the signal), but on the other hand you have to spend a moment with them to understand what you hear.

Some things will be clear, however, from the first song on the first album you will listen to - in my case it was the TBM Sounds! released in 2003 by Mr. Winston Ma as part of his sub-label Lasting Impression Music, and the track was the Shoi Yokuchi Trio Greensleeves, from the album of the same title.

And what did I hear? - First of all, excellent dynamics and great differentiation. The recording starts with an acoustic guitar, first plucked with fingers, then with a pick and again with fingers. For those who play this instrument or listen to it often, the differences in the sound of these techniques are perfectly legible, and what they can hear is the fact that the guitar played with fingers sounds darker and a bit dull, and the pick extracts more aliquots and higher midrange from it.

The cable from Australia showed these differences very nicely - it differentiated the performance, but did not distort it by emphasizing one type (dark, warm) or the other (hard, light). What's more, it showed fantastic dynamic differentiation of this recording. You see, the Three Blind Mice label is known for its excellent recordings, and they used many interesting techniques. For example, some recordings were made on a modified Philips multi-track tape recorder with a tape speed of 76 cm/s (!), while the top standard speed is 38 cm/s and even it is considered by many engineers to be an exaggeration.

And Greensleeves is another story - this is probably the only (I have to check it out) album from this label recorded on a reel-to-reel tape recorder (if I understand correctly - there is the PCM logo on OBI); and it was released on vinyl. There is a lot of interesting things to talk about concerning this release, but dynamic contrasts particularly draw attention - they are incredible. And the FoilFlex cables conveyed it very accurately - almost as well as the Siltech Triple Crown cables, they were compared to. Silver cables from the Netherlands sound darker, have a more velvety background, but these differences were quite small.

Which I confirmed quickly by listening to the Dave Grusin Discovered Again Plus from the XRCD24 disc. This is a recording originally made in the direct-to-dics system and released on the LP. Parallel to cutting out the lacquer, however, a backup copy was made - straight to analog stereo tape. This is an extremely dynamic recording, open but never bright. FoilFlex showed it all nicely, beautifully presenting both color and dynamic ranges.

There are two things that distinguish it from reference cables. On one hand it's a slight rounding of the bass. It is well extended and dynamic, but it not so contouring, i.e. equally legible. There were no problems with it, but I say it how it is. In turn, the other band’s extreme sounded a bit stronger. Maybe it wasn't as much about the timbre itself, or the volume of treble, but rather about their character - they were more energetic.

This difference, i.e. opening of the sound without brightening it up, was best heard with the Bill Evans Trio Portrait in Jazz. For years I listened to it from the K2HD version, even though I had the 2003 release on the SACD. That is until I heard it on my player, the Ayon CD-35 HF Edition. That's when I understood what the top SACD player had to offer with SACD disc - I got a dense, very natural sound with a dark character. Because this version sounds like that. There is a lot of noise in this recording, there is not much treble and the bass is hardly legible. And yet it sounds incredibly natural.

The Australian speaker cable slightly changed its character, opening the upper midrange. The change was not big, but important for the performance. Because these are cables that, on the one hand, sound dark and warm - which could be heard with the Three Blind Mice recordings - and on the other in an open way, showing a lot of information from the top of the band. This darkness, I think, results from excellent resolution, and openness from a slight accent on the attack.

It was very well arranged, orderly, good performance of a particular character. And there was also proper space and imaging that the cable offers. 3D bodies are not clearly marked, but they do not blend with the background. In turn, the space, its dimensions, both in depth and in depth, are perfect. Vangelis' soundtrack for the Blade Runner (1982, by Ridley Scott) shone with a multitude of details presented on a large soundstage, in a wide perspective, as in a panoramic cinema. The foreground was placed quite close to me, but without stepping in front of the line connecting the speakers. And it had something else - great depth, which added dynamics and drama to the performance.

This particular sonic character means that with Australian cables you will enjoy recordings that do not offer the best possible resolution - like the soundtrack to the movie Gladiator directed by (again) Scott - but they will also offer great experience with top recordings, like the ones I talked about earlier. I mentioned the Gladiator for a reason. A few days earlier I went to The World of Hans Zimmer - A Symphonic Celebration series concert, which allowed me to listen to Lisa Gerrard live, so comparing this performance with the recording was an obvious choice to me.

On the album, Gerrard's vocals are set higher than how the sound engineer during the concert did, but it is also clearly younger - hence its center of gravity is set higher. The FoilFlex cable showed this difference perfectly, while maintaining the consistency of the recording. The sound was still not very selective, the orchestra was slightly suppressed (that’s how it sounds on the CD), but - paradoxically - with a cable like the tested one it had a bit more life, more energy than with a reference cable. Which turned out for good for this recording.


New mixes of classic albums, say, The Beatles Abbey Road, or a new version of the album In The Court of the King Crimson (An Observation by King Crimson), are better internally organized and have more creamy colors than the originals, they are also more dynamic. That's how FoilFlex cables sound like. Everything in their sound has its place, is organized, makes sense. Their colors are saturated and full, with the upper midrange and treble saturated with high energy. The lower bass, on the other hand, is rounded and not very selective.

But I say this, comparing them to the extremely expensive competition, to the best speaker cables I know. And even in this comparison Australian cables surprised me with excellent dynamics, speed and slam. Because these are just very good cables. They sound neutral, but also natural, show a lot of details, but are not overly detailed. You can hear that it is a product that came from love - love of music.


Reference system 2018

1) Loudspeakers: HARBETH M40.1 |REVIEW|
2) Line preamplifier: AYON AUDIO Spheris III Linestage |REVIEW|
3) Super Audio CD Player: AYON AUDIO CD-35 HF Edition No. 01/50 |REVIEW|
4) Stands (loudspeakers): ACOUSTIC REVIVE (custom) |ABOUT|
5) Power amplifier: SOULUTION 710
6) Loudspeaker filter: SPEC REAL-SOUND PROCESSOR RSP-AZ9EX (prototype) |REVIEW|
7) Hi-Fi rack: FINITE ELEMENTE Pagode Edition |ABOUT|


Analog interconnect SACD Player - Line preamplifier: SILTECH Triple Crown (1 m) |ABOUT|
Analog interconnect Line preamplifier - Power amplifier: ACOUSTIC REVIVE RCA-1.0 Absolute-FM (1 m) |REVIEW|
Speaker cable: SILTECH Triple Crown (2.5 m) |ABOUT|

AC Power

Power cable | Mains Power Distribution Block - SACD Player: SILTECH Triple Crown
Power (2 m) |ARTICLE|
Power cable | Mains Power Distribution Block - Line preamplifier - ACOUSTIC REVIVE
Power Reference Triple-C (2 m) |REVIEW|
Power cable | Mains Power Distribution Block - Power amplifier - ACROLINK Mexcel 7N-PC9500 |ARTICLE|
Power cable | Power Receptacle - Mains Power Distribution Block: ACROLINK Mexcel 7N-PC9500 (2 m) |ARTICLE|
Power Receptacle: Acoustic Revive RTP-4eu ULTIMATE |REVIEW|
Anti-vibration platform under Acoustic Revive RTP-4eu ULTIMATE: Asura QUALITY RECOVERY SYSTEM Level 1 |REVIEW|
Power Supply Conditioner: Acoustic Revive RPC-1 |REVIEW|
Power Supply Conditioner: Acoustic Revive RAS-14 Triple-C |REVIEW|
Passive filter EMI/RFI: VERICTUM Block |REVIEW|


Speaker stands: ACOUSTIC REVIVE (custom)
Hi-Fi rack: FINITE ELEMENTE Pagode Edition |ABOUT|
Anti-vibration platforms: ACOUSTIC REVIVE RAF-48H |ARTICLE|

  • HARMONIX TU-666M "BeauTone" MILLION MAESTRO 20th Anniversary Edition |REVIEW|


Phono preamplifier: Phono cartridges: Tonearm (12"): Reed 3P |REVIEW|

Clamp: PATHE WINGS Titanium PW-Ti 770 | Limited Edition

Record mats:


Headphone amplifier: AYON AUDIO HA-3 |REVIEW|

Headphones: Headphone Cables: Forza AudioWorks NOIR HYBRID HPC