Roboden Elastic Cable - A Great Idea Finally at a Reasonable Price
July 8 2021, 18:00
An elastic cable? Roboden is a unique stretchable cable for microphones and headphones. It expands up to 40% longer, has low microphonics, and looks and feels premium! Mike Klasco writes about it, now that Hightek, an OEM cable manufacturer from Taiwan has licensed the technology. Finally, stretching cables are in the BOM range of quality consumer electronics products. This article was originally published in The Audio Voice newsletter, July 2021.
Roboden, a unique stretchable cable with great potential for microphones, earphones, and headphones, expands up to 40% longer than its "at rest" length. Originally developed a decade ago for use in robotics and industrial machinery where cables need to glide around joints that pivot or extend, Roboden stretches and shrinks to fit as needed. The consumer electronics applications range from wall wart power supplies that won’t knock over your laptop, or send your smartphone flying when the cord is tripped over, to wearables without the cable flopping when you are moving around.
A few years back I wrote for the first time about this great development with major implications for audio applications and consumer electronics in general. Developed originally by Asahi Kasei of Japan, this braided wire cable stretches and shrinks to fit as needed. For several years now, I've been carrying samples and fully-functional "stretchable" cables to every trade show I attended, and every time the reactions are exactly what manufacturers wish they would have with every single product release: I want one!
Roboden is a unique stretchable cable with numerous applications that was originally developed by Asahi Kasei of Japan, and is now manufactured by Hightek in Taiwan.
Another appealing attribute of the Roboden cable construction is low microphonics, crucial in applications such as lapel (lavalier) microphones, in-ear-monitors and all types of earphones, minimizing bio-body noise reaching your ears. This will be especially appealing to cable designers because while braided sheaths look classier than extruded PVC and TPE outer insulations, woven jacketing tends to create and carry body vibration noise to the earphones.
The inside of this cable has an elastic core and wire is wound around in a spiral. A second stretchy sheath covers the entire thing. The unique Spandex/nylon fiber weave topology with a stretchy silicon “spine” effectively absorbs microphonics. The spiraled wire means there is enough inside the cable to allow it to act like a "Slinky". Sport fitness, electronic news gathering (ENG), or even a guitarist hopping around on stage could all benefit from Roboden elastic cables.
Unfortunately, the path to market has been a long haul. Japanese giant Asahi Kasei (you may know the name because of the famous AKM converters) spent years developing Roboden and while the product functionality was fabulous, so was the pricing - well beyond the reach of even premium consumer products! Now Asahi Kasei’s cable subcontractor, Hightek, has licensed the technology. Hightek is a Taiwan public company that is an OEM cable vendor to Sony, Acer, HP, Dell, Asus, and others, with about 20% of the global in-box cable business. With the company's streamlined supply chain, there is now a stretching signal cable that is in the BOM range of quality consumer electronics products.
How can a cable stretch and contract? Roboden’s structure consists of conductor wires wound in a spiral configuration over an elastic body, and covered in a braided outer covering.
Roboden cables maintain a certain gap between the conductors, with stable characteristic impedance, offering excellent signal transmission integrity regardless of whether the cable is fully extended or at rest. Applications for Universal Serial Bus (USB) technology are particularly relevant since the use cases are increasing exponentially. USB specifications limit the length of the cables, which require certification, particularly for the most recent USB Power Delivery specification. Hightek already offers USB-C cable options, which will meet the specifications at 1 meter length, while being able to stretch the distance when required. Versions for greater lengths and greater bandwidth are on the way.
Charging stretch cables, typically configured captive to the wall wart are expected to be in great demand. Anyone who has tripped over a cable by accident and sent something expensive crashing to the floor will attest that current USB cables don't stretch at all. No matter how well the cables are coiled on devices, a day inside a backpack always manages to unravel the wire and leave a mess of spaghetti. With Roboden, the cable will remain coiled up if a little stretch is put in when winding it tidily — just like a bungee cord.
A premium Roboden elastic cable with MMCX connectors used for converting standard in-ears into a wireless solution. The non-microphonic cable will remain coiled up if only a little stretch is put in, and won’t pull the earphones out the user’s ears.
Applications in incredibly expensive in-ear monitors, or even as an option to connect Bluetooth sports fitness earphones are appealing products. Roboden bypasses the serious design, performance, and value challenges, with no microphonics. The soft silicon core provides just enough tension that the cable won't flap around or pull the earphone out of your ear — while providing up to eight conductors between the two earpieces.
Hightek is now looking for supply chain partners for Roboden, including OEM/ODM customers and brands to integrate Roboden into their products, as well as the aftermarket through local stocking distributors for in-box cables, and the aftermarket for upgrade of conventional cables.
This article was originally published in The Audio Voice newsletter (#335), July 2021.
Updates to the USB specifications, particularly the need for certification in new USB Power Delivery applications, poses challenges. These stretchable USB-C cables can extend the length limitations within the spec.
About Mike Klasco
Mike Klasco is the president of Menlo Scientific, an audio consulting firm for the audio and loudspeaker industry, located in Richmond, CA. He is a graduate from New York University, with post graduate work in signal processing, and he holds multiple patents l... Read more
