Earphone cable wire question - Page 1
Forum section: electronics / general

author: kalel
author_rank: Frequent Contributor
timestamp: January 23, 2018, 09:17:18 am
content: I saw this image on a KZ ED4 advert:My question is both about the "bulletproof fiber" and copper wire.As for the fiber, do you know what it is and what its general properties are? I guess it's a relatively elastic material to allow for partial bending.As for the copper wire, is it wrapped around the fiber core as one huge coil? If so, do you know why this method is preferred - if it is - over general insulated multi-core wires?Also (if it is wire wrapped around the core) does this method create any significant inductance, and could that have any effect on the signal at all.I guess this is relatively standard for various earphone cables, I'm just curious about the composition. I'm not looking for details, just the general info on how this works.If it is one huge length of wire wrapped around each core, then I don't understand the 56 cores mentioned. Perhaps on each core, there are multiple wires wound. Of course, if one (or a few) of them breaks, you still have the signal. With just one - unless it is thick - signal could be lost easily.

author: Someone
author_rank: Super Contributor
timestamp: January 23, 2018, 09:45:58 am
content: Its an artists impression, not an accurate image and simply marketingnonsensepuffery as it literally cannot be lossless. Many headphone brands have been using kevlar/aramid reinforced cables as the protect the copper so it fractures less often.

author: Zero999
author_rank: Super Contributor
timestamp: January 23, 2018, 11:18:04 am
content: Yes, it's marketing wank. None of this improves sound quality. There's no need for oxygen free copper or extremely low resistance, for a headphone cable. It's all nonsense.Having lots of cores is fairly standard practise because it helps the cable flex more without breaking. As mentioned above, kevlar/armed reinforced headphone cables are often used for mechanical strength.

author: kalel
author_rank: Frequent Contributor
timestamp: January 23, 2018, 11:20:07 am
content: I was more curious about the construction technique than the lossless claims (especially on a sub $8 earphone). Whatever loss there is, I'm sure it won't really be matter and/or be noticable. So the "bulletproof fiber" could be kevlar? In fact, for earphone cables the most important thing I can think of is durability over time.

author: ajb
author_rank: Super Contributor
timestamp: January 23, 2018, 06:18:54 pm
content: Often for thin cables that will encounter a lot of abuse the conductors are twisted together with fibers for strength and flexibility. This is an enhancement over larger cables that sometimes have fibers between individual wires inside the jacket (in which case they also help to fill out the jacket so it's more consistently round). It makes the wires a bit harder to terminate, having the fibers mixed into the copper, but improves flexibility. Whether or not the fibers are kevlar, who knows.

author: Ian.M
author_rank: Super Contributor
timestamp: January 23, 2018, 06:46:33 pm
content: Kevlar is relatively expensive and has rather poor fatigue resistance. It also has a characteristic pale yellow-brown colour in its undyed state. Just about any other low stretch fibre would be preferable unless you need Kevlar's high temperature resistance.

author: nfmax
author_rank: Super Contributor
timestamp: January 23, 2018, 06:47:23 pm
content: A story: once upon a time (in a galaxy far, far away) I was part of a team designing airborne test instrumentation for helicopters. Part of this was a camera-like device, fixed externally to the airframe, looking up at and measuring movement of the main rotor blades. This was connected by a multi-core screened cable to the main instrumentation unit, which was normally strapped down somewhere handy in the cabin for the test flights. The cable construction was similar to that in the OP's picture: lots of fine strands in each core for flexibility, a Kevlar strength member, and in our case a highly abrasion resistant polyurethane outer jacket.A customer told us they were flying this system, with the cable routed in through the open window of the cabin door, when for some reason the door hinges came off in flight, releasing the door (they are designed to do this, so the aircraft can be flown 'doors off' for best pilot visibility, but this is only supposed to be possible on the ground). Our cable held the door, (which otherwise would probably have gone into the tail rotor, ruining everyone's entire day) until the pilot was able to make an emergency landing.

author: james_s
author_rank: Super Contributor
timestamp: January 23, 2018, 07:42:57 pm
content: Wow, it seems like they'd have some sort of safety cable integral to the airframe to prevent a loose door from falling off in flight. Ruining the day would likely be an understatement if it went into the tail rotor.

author: @rt
author_rank: Super Contributor
timestamp: January 24, 2018, 01:15:05 pm
content: My new Senheizer earbuds arrived last week after the last ones that gave me five years stopped working on one side.I was unable to break the cable before strangling my fingers until the pain was too intense.The outside sheath stripped, but that was all.

author: kalel
author_rank: Frequent Contributor
timestamp: January 24, 2018, 03:50:48 pm
content: Quote from: @rt on January 24, 2018, 01:15:05 pmUnfortunately, these are not easy to fix/solder. I guess that's the price of high durability cables. Still, 5 years is very good, so maybe they do use superior cable to cheaper stuff. Sometimes it's not just the cable itself that is the problem, but strain relief around any solder joints and connectors. What model were they?

author: james_s
author_rank: Super Contributor
timestamp: January 24, 2018, 07:29:18 pm
content: Mine usually fail right at the plug, not surprising since it gets a lot of bending there. I use cheap earbuds though, not really worth trying to repair.