Estron's Linum BaX MMCX cable fitted to a Westone UM Pro 20
At only ~0.9 mm in diameter, the Linum really is as thin as it looks; when I first spotted these cables, I nearly mistook them for fishing line, so for a while I thought Estron was promoting the revival of the string telephone! I quickly found out that the Linum is far from a child's plaything, however. Heaps of material science and industrial testing have gone into the development of this cable.
At only 0.9 mm thick, the Linum MMCX cable is dwarfed by a stock Westone EPIC2 cable.
The Estron website for showcasing the Linum cables is highly informative, so I'll let them describe the makeup of the cable in techno mumbo-jumbo:
6 litz conductors made up of 7 individual strands. Each strand is silver plated copper with enamel. It will not corrode or change colour . The strength comes from aramid fibres.
Pull strength is 60N (~13 lb.) The jacket is made from TPA. It is skin-friendly approved and UV stabilized, so it will not turn yellow if exposed to sunlight.
What all this means is that, despite its lithe appearance, the cable is damn strong and built tough. Even though it has fewer conductor strands than other cables, each wire is a Litz design, meaning that each individual SPC strand is enamel-coated for signal isolation. The enamel and silver-plating also combat wire discoloration due to oxidation of copper.
The kevlar-reinforced (individual strands of aramid) thermoplastic elastomer (TPE-A, TPA) jacket is really strong; over the last few weeks, I've taken it out on the streets, tugged roughly on it, threw it around, turned it into a tangled mess, and nothing fazed the cable. I've gone jogging with the cable, walked around crowded streets and underground passageways; the only thing I'd be worried about for this cable is the off chance that a lunatic takes a scissor to it and tries to snip off a section! At the same time, the cable is incredibly soft. Although it might look like a fishing line, the Linum cable is way more pliable and far less springy.
Thus, I really believe that TPAs are the material of the future for cables; I've already seen them used in cables from Chinese companies like Astrotec and Ostry, so they seemed primed to take over the market from the old guard of PVC, PTFE, and PE. They seem environmentally stable and can be polymerized for a variety of densities and extrusion patterns, making them ideal for cable protection.
FYI, Estron uses Pebax, a proprietary polyether block amide blend from Arkema.
These thin cables can take a beating!
In addition to the common 2-pin (0.78mm) and MMCX variants, Estron has also developed a special connector they call the 'T2'. They claim that it can withstand thousands of pulls and insertions without loosening (as it inevitably happens with 2-pin connectors) or intermittent signal loss (as MMCX connectors are prone to). Presently, only Cosmic Ears CIEMs offer the option for this kind of connector, so I didn't test it.
The conventional options are well-done, however, and people should not worry about the quality of these small connectors. The 2-pin overmold is actually very sturdy; it's just a tad bit small for me and thus requires some manipulation to remove. On the other hand, the MMCX connector behaves much like any other MMCX connector cable on the market today. Luckily, because of the cable's low mass, the Linum cable will not spin around like the stock cables on Shure and Westone earphones.
The MMCX (left) and 2-pin (right) variants of the Linum BaX cable.
Interestingly, the indicators for left and right leads for the MMCX connectors are located on the neck slider; a single red dot on the side of the slider denotes the side of the right connector. It might be a little inconvenient for people to slide the neck slider all the way to the hilt in order to check L/R every single time.
The red dot shows you which side is right.
With regard to sound, I dislike saying too much, as people tend to draw their own conclusions when it comes to cable sound. Interestingly, Estron has opted to go with three different variants of the Linum cable: Music, Vocal, and the currently examined BaX.
The difference between the three variants is mostly the intrinsic resistance and inductance of the conductors themselves. In terms of DC resistance, the Music variant is 1.9 ohms, the Vocal is 3.9 ohms, and the BaX is 1.4 ohms. For reference, the highest purity silver-plated OCC cables can sometimes exhibit resistances of <0.7 ohms.
Of course, actual impedance characteristics depend on the inductive and capacitive characteristics of each individual cable, but DC resistance can be a direct comparison in terms of the effect that a cable can have on frequency response. Most removable cable IEMs are balanced armature based with wildly variable impedance response curves, so cables with different resistance will clearly affect the frequency response of the earpiece.
Estron has done some rudimentary tests to highlight the different effects of their cables. As Estron has a special relationship with CIEM manufacturer Cosmic Ears, CE was their pilot test subject. Here's a video of CE testing the different variants (Music, Vocal, BaX) of the Linum line:
Estron's explanation to me was that the BaX cable served as a "loudness" modifier, lifting the low end and upper end, as well as increasing overall sensitivity, as per Fletcher-Munson curves.
However, my personal rule has alway been to choose the cable with the least DC resistance and least overall impedance, as to make the cable effect negligible. That's why I chose to test the BaX variant. As the only cable made in a dual twist configuration, it shows the least resistance and impedance. The BaX variant is also best for head-fiers because it does not have a separate solder joint at the Y-split, but is instead four conductors all the way down to the 1/8" termination, potentially reducing stereo crosstalk (given a well-managed ground from your amp, of course). If you had the time and patience, you'd even be able to re-terminate a BaX cable for balanced output!
The dual twist configuration of the BaX obviates the need for a re-solder joint at the Y-split.
The only downside to the twisted-pair configuration of the BaX is that it does not have the "tangle-free" feature of the Music and Vocal variants; the TangleFree option, judging from a video shown to me by Estron executives, looks to be extra Kevlar reinforcement on the cable sheathing to give it a definite coiled pattern so that the cable will gently spring back into shape. Considering the benefits of the twist pattern on the BaX, though, I'd say that the electrical benefits outweigh the ergonomic drawbacks.
It's difficult not to be impressed by the Estron Linum. It'll easily be the thinnest and lightest IEM cable you'll ever see, and considering the crazy variety of IEM cables out there, that's a tall order! It's no wonder that even Westone is testing this cable as an alternative to their EPIC cables for professional use.
Even though their primary business seems to be related to ODM/OEM, behind-the-scenes type of stuff, Estron seems like a company ready and willing to engage the public. Their reps have been nothing but informative and transparent with their disclosure of the cable specifications, as well as being as courteous as can be. I've had many pleasant interactions with their team, namely Annette and Lisbeth, as well as their president, Allan Sorrig. Although I've never personally met them, the word is that they've been touring various different audio shows, both professional and consumer-oriented, to gauge public interest in a product like the Linum. Perhaps it's the Danish heritage of Estron --- Denmark is well-established in the world of hi-fi, and thus it's possible that this standing prompted Estron to explore the world of personal audio, rather than to remain catering just to professionals. Even though they sell direct from their own website, in addition to Cosmic Ears, the Jaben Network is said to be an official distributor, as well as Japan audiovisual giant Fujiya-AVIC.
The bottom line is that if you are happy with the stock sound of your IEM, but desire a cable that is much lighter and much lower profile, consider the Linum BaX. If you are a stage musician and need a thin, light cable that can blend invisibly with your performance attire, strongly consider the Linum BaX --- this cable really is made for you. It's strong, it's featherlight, and it's nearly invisible.
EDIT: fixed some links
Edited by tomscy2000 - 5/30/14 at 11:40pm