Sourcing TWS earbuds from China

Acoustic tuning. The same driver in the same housing sounds different depending on the vent geometry, the damping material and the equalisation applied in firmware. This is the largest part of perceived quality and it is invisible in a parts list. Ask whether the tuning is the factory's own or the reference design's, and whether it can be changed for you.

Antenna and connection handling. Most complaints about earbuds are connection complaints: dropouts when the phone is in a pocket, one bud losing sync, stutters in a crowd. That is antenna placement, the pairing scheme between the buds and the firmware's recovery behaviour. Test it by walking around with the phone behind you, in a busy place, not by sitting at a desk.

Microphones and call processing. Call quality is where cheap earbuds are worst, and it is the use most buyers actually care about. Number and placement of microphones, whether there is a bone-conduction or wind-noise path, and the processing behind it. Test on a real call, outdoors, in wind, with traffic.

Fit and housing. An earbud that falls out is a failed product regardless of its measurements, and fit is a physical design problem across a range of ears. Test on several people, in motion, not on one head at a desk.

Case behaviour. Hinge and magnet feel, whether both buds seat reliably, whether the case charges them every time, and what the case does after a hundred open-close cycles. The case is the part a customer touches most and the part most often cost-reduced.

The chipset decides the ceiling. It sets which codecs are available, the low-power behaviour, the ANC architecture and how much the firmware can do. Ask which chipset, which firmware version and who can modify it — the answer tells you whether a field problem can be fixed or only replaced.

Licensed codecs are a commercial matter, not a specification line. Some codecs are freely implementable and some require a licence from their owner, usually tied to a specific chipset. A supplier who lists a licensed codec on a product built on hardware that does not support it, or without a licence, has put a claim on your box that you will be answering for. Ask for the evidence.

Active noise cancellation is a design, not a number. Feedforward, feedback and hybrid architectures behave differently, and the quality depends on microphone placement, seal and tuning far more than on any published attenuation figure — which is measured differently by every supplier and is meaningless without the test condition. So no dB figure appears on this page. Compare samples in the environment you care about: an aeroplane cabin recording, a train, an office.

Battery and runtime claims. Runtime depends on volume, codec and whether ANC is on, so a single headline number is a marketing artefact. Define the test — volume level, codec, ANC state — and have the runtime measured to your definition, then base your packaging claim on that.

Bluetooth qualification first, because it is the one most often missed. Membership of the standards body plus a qualified design with a Declaration ID, listed against a member company. If you are branding a factory's design, establish whose qualification you are relying on and whether your version needs its own listing — and remember that the word marks and logos are trademarks, so printing them is a licensing question as well as a technical one.

Radio approval per destination. A Bluetooth device is an intentional radiator, and each market has its own regime for that: the EU and UK expect the technical file and marking, the United States its own equipment authorisation, and Japan and Korea their own national approvals. These are separate from the Bluetooth qualification and one does not substitute for the other.

Water and dust ratings. An IP rating is the result of a defined test, so ask which test was performed, on which model, by whom, and get the report. A rating claimed for the earbud does not cover the case, and a rating measured on a pre-production unit does not describe a production run whose housing seal was later changed.

Battery paperwork. Earbuds and cases contain lithium cells, so the transport documentation applies. The guides on watt-hour conversion and shipping lithium batteries by air carry those thresholds; this page deliberately does not.

And remember the obligation follows the brand. Selling under your own name generally makes you the manufacturer for regulatory purposes, so the technical file and the traceability are yours, not the factory's whose certificate you were shown.

Specify: chipset and firmware version, driver type and size, tuning ownership, microphone count and arrangement, ANC architecture, codecs with evidence of the right to claim them, case capacity and cycle life, charging input, IP rating with the test report, housing material and finish, and the exact marking on the product and the case.

Buy at least five pairs, not one. Fit and connection behaviour vary between units and between ears, and a single good sample is the least informative outcome available. Give them to five different people for a week.

Test in the real world: walking with the phone in a back pocket, on a call outdoors in wind, in a busy station, at the gym, and after leaving the case in a warm car. That list finds more problems than any bench measurement.

Then take a pair apart. Driver, vent, damping, microphone placement, antenna, battery marking and how the housing is sealed. The teardown explains a price gap that a specification sheet cannot.

Every supplier on this site is a manufacturer, and the registered-scope check is one of the things confirmed before a listing goes live — which matters here because audio is a category with an unusually deep layer of assemblers selling one reference design under many names.