Earphone Memory Wire Cable with Formable Ear Hook

What an earphone memory wire cable has to survive

An earphone memory wire cable has to do two jobs that pull against each other. It has to hold the bend set at the factory, survive the wearer re-shaping it every time the earpiece goes in, and keep that shape through pocket heat and bag crush. At the same time it is still a cable: audio conductors, often a microphone pair, sometimes control lines, all packed into the section that gets bent more often than anything else on the product.

The build we run most often puts enameled copper and a stainless shaping wire in one cable. The copper carries the signal. The steel core does no electrical work at all; it simply holds the shape. That division is what lets an ear hook stay where you put it without a clip, a molded stiffener or an external stay. Winding the conductor around the core rather than laying the two side by side keeps the section round and keeps it to one cable instead of two that would need taping or sleeving later.

Formable is the word that matters here. Read the next section before you send us a drawing.

Formable is not shape memory, and mixing them up costs a sample round

Two very different materials get sold under the name memory wire, and confusing them is the fastest way to waste a round of samples.

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	Formable stainless (what we build)	Shape memory alloy (what we do not)
What it does	Stays where you bend it	Springs back to a trained shape when heated
Mechanism	Plastic deformation of the metal	Solid-state phase transformation
Typical material	Stainless steel shaping wire	Nickel-titanium alloy
Fits	Ear hooks, headset positioning, routing that has to stay put	Actuators, latches, thermal triggers
Relative cost	Low	High
Termination	Crimp, weld or captured in the overmold	Crimp or resistance weld; will not take solder

We build the left column. If your headset needs a wire that actively pulls itself back to a trained curve when current or heat is applied, that is a shape memory actuator, it belongs to a different supply chain, and it is not what this page covers. Tell us early and neither of us spends money finding out.

Which core does the ear hook need?

The core decides how the hook feels in the hand and how long it lasts, and it is the first thing to settle.

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Core type	How it behaves	Where it fits
Single solid wire	Crisp bend, firmest hold, lowest cost	Over-ear hooks on light headsets
Stranded or bunched core	Softer hand, gentler curve, survives more re-bending	Sports and call-center headsets re-shaped daily
Served bundle (textile or film wrap over the core)	Shields the enamel from the steel, longest bend life	High-cycle products, thin enamels, tight hook radii
Twin or flat core	Resists twist, keeps the bend in one plane	Hooks that must not roll off the ear

The fastest way to settle it is to tell us the curve the hook has to hold and roughly how many times it will be re-bent in service. Those two answers narrow the field faster than any datasheet.

Why the ear hook is the first thing to fail

On this construction the enameled conductor sits directly against a steel core, so every re-bend rubs the coating against metal that is harder than the coating. Enough cycles and the enamel goes through: the copper touches the core and you get a fault that only appears when the hook is held at one particular angle. In the field that shows up as crackle, dropouts or one channel cutting out when the wearer turns their head.

Three things set how long that takes. Bend radius is the biggest: a tight hook loads the winding far harder than a gentle curve. The second is whether anything sits between the copper and the steel, which is what the served core in the table above is for. The third is the enamel grade, and that one carries a real trade-off.

Solderable or scrape-resistant enamel: pick one for the hook

The coating on the conductor has two jobs that pull in opposite directions. It has to survive being rubbed against steel, and it has to come off cleanly at the ends so the conductor can be terminated.

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Enamel family	Comes off in a solder pot	Abrasion resistance	Choose it when
Solderable polyurethane	Yes, at the temperature your wire supplier specifies	Moderate	Termination yield and speed matter most
Solderable polyester or polyesterimide	Yes, at a higher bath temperature	Good	You need a higher thermal class and solder stripping
Standard polyesterimide, polyamideimide, polyimide	No, needs chemical, mechanical or laser removal	Very good	Bend life dominates and you can accept slower stripping

Solderable coatings come off with controlled immersion, stripping and tinning the strands in a single pass. We will not pretend that works for every enamel, and if the grade on your drawing calls for chemical, mechanical or laser removal we will say so before quoting. On fine headset conductors the stripping method drives yield, so it is worth settling early.

For background on the equipment this construction serves, see the general reference on headphones.

Where the cable ends: earphone housing, plug and microphone

Solder will not wet stainless the way it wets copper. Ordinary rosin flux leaves a cold joint, and anything aggressive enough to bite into the steel leaves residue we would not want on a headset. In most builds the core is not part of the electrical path at all: it is crimped, spot welded, or captured inside the overmold at the strain relief so it cannot migrate.

Adding a microphone or an inline control changes more than the conductor count. More conductors mean a bigger bundle, a larger jacket, and a hook section that behaves differently; usually the core diameter has to come down to keep the same hand feel. We settle conductor count and core diameter together for exactly that reason, and it is cheaper to do on paper than on a second sample round. Where the headset end has to be a serviceable plug rather than a fixed cable, our Plantronics headset bottom terminal cable and Plantronics headset QD cable are built under the same discipline; for tight housings that need the plug to exit at an angle, see the 3.5mm TRRS 4-pole right angle cable.

Jacket, hand feel and what the wearer notices

The hook is the part the customer actually touches, so jacket choice is a product decision and not only an electrical one. Soft-touch compounds feel better against skin and stay flexible in the cold. PVC costs less and takes color well. Silicone is the softest and the most resistant to sweat, but it picks up lint. Each one creeps differently over time, which matters because the jacket itself contributes to how well the bend holds.

We do not certify a jacket to any particular skin-contact or safety standard. You specify the material and the documentation you need, and we build to that.

What we need from you to quote

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Item	Why it moves the quote
Hook curve and bend radius	Sets core type, stiffness and bend life
Re-bend cycles expected	Drives core and serving choice, and qualification testing
Conductor count and size	Sets what the cable carries and its overall diameter
Enamel grade	Decides the stripping process and the tool set
Jacket material and color	Hand feel, cleaning and lead time
Terminations at both ends	Drives tooling; we cut our own molds
Length, tolerance and quantity	Standard quoting input

How we build and inspect them

Assembly runs in Shenzhen on four lines with around forty operators, and tooling is cut on site, so a custom overmold does not push the schedule out by weeks. Minimum order is typically 500 pieces, samples go out in roughly three days, and a production run takes about two weeks, process dependent. Each cable is built and inspected to IPC-WHMA-A-620 Class 3 and gets a 100% continuity and pinout check before it ships. Straight audio leads for the same program run through the same bench, as with our 3.5mm stereo Y splitter cable. Where a design is better served by a cable that retracts than one that holds a shape, start from a coiled retractable cable, and for this construction in its most general form see the memory wire composite harness.

Frequently asked questions

Everything on this page is general guidance. Each cable is built and inspected to your drawing.