Tech

How in-ears work and influence our listening habits in the future

A good five years ago, the Munich startup called Bragi launched the first completely wireless in-ears that were connected to smartphones via Bluetooth – and thus started a small technological revolution. Apple’s big market breakthrough came a year later with the AirPods, which could be easily paired with Apple devices. You can now meet their porters in every tram.

Bragi used a transmission technology from the hearing aid industry for its in-ears called Dash: NFMI (Nearfield Magnetic Induction). It enables one earphone connected via Bluetooth to transmit audio data to the second earpiece over a distance of about 30 centimeters with a magnetic induction field. The advantage of NFMI are relatively short latencies, the disadvantage is a certain susceptibility to high-frequency sources of interference, such as those used for theft protection in department stores.


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The revolution could have started in 2008, when the largest German headphone manufacturer Sennheiser released its first completely wireless in-ears called the MX-W1. At that time they still used the Bluetooth alternative Kleer. “We were ahead of the times,” explains Frank Foppe, Global Product Manager at Sennheiser. Just like Betamax in the case of video cassettes, Kleer was unable to establish itself despite technical advantages and was not built into smartphones.

Sennheiser launched the first wireless in-ears MX W1 back in 2008. However, because they used Kleer instead of Bluetooth for transmission, they could not establish themselves.

(Image: Sennheiser)

Sennheiser’s wireless Bluetooth in-ears Momentum True Wireless only followed in 2018. Like Bragi, these used NFMI technology for transmission and achieved comparatively short latencies of around forty milliseconds. “In the meantime, however, Bluetooth has gotten better,” explains Foppe. The second generation Momentum True Wireless 2 no longer uses NFMI, but instead couples both earphones via Bluetooth, similar to what Apple does with its proprietary protocol for AirPods. This increases the latency to well over a hundred milliseconds, however, reduces power consumption and susceptibility to failure.

Not least thanks to efficient Bluetooth implementations, the power supply is hardly a problem for a manufacturer today, as our current comparison test shows. Most models last well over four hours and can be quickly recharged in battery-operated storage boxes.

What the manufacturers are still working on is the fit, among other things. Apple’s original AirPods are made of solid plastic. They neither adapt to the shape of the ear nor do they hermetically seal the ear canal. This is why they don’t sit particularly well in some people’s ears or they squeeze after a while.

If the ear canal is not hermetically sealed, it is particularly difficult to transmit low bass frequencies. That is why most manufacturers now use flexible rubber sleeves, which they often include in several sizes. The bass transmission works, but such terminations also amplify the body’s own noises – experts speak of the occlusion effect. Walking movements or one’s own language then sound very dull.

Only a few manufacturers have solved the problem so far: Apple records the body’s own noises in the AirPods Pro using microphones in the ear canal and compensates for them with the help of counter noise and air inlets. Samsung also dispenses with air-tight cuffs on the Galaxy Buds Live, built in additional air inlets and, thanks to a new development from AKG, has been able to increase the bass reproduction enormously. As a third member of the group, Huawei is now using air inlets in its in-ears to reduce the occlusion effect. With current in-ear models from suppliers such as Bose, Nura or Sennheiser, however, the occlusion is still a problem.

Like Apple, Samsung builds special air vents in the Galaxy Buds Live to reduce the occlusion effect.

(Image: Samsung)

Athletes also often have the problem that the wireless plugs easily slip out of their ears. Two methods ensure a tighter fit: some models grip the ear with small rubber fins, while others have to be attached behind the outer ear with additional brackets. The latter is “bombproof”, but also very fiddly when putting it on and taking it off and bothers people who wear glasses.

Since each ear is individually shaped, tests in magazines or YouTube videos can be of little help in choosing the right fit. Ultimately, you have to try the in-ears yourself. Despite the included cuffs in different sizes, your ear may be too big or too small.

The manufacturer Scheinhardt offers earmolds for AirPods and other in-ears. A hearing care professional takes impressions. To charge in the case, you have to remove the fitting pieces again.

(Image: Scheinhardt)

If nothing fits, ear molds from hearing aid acousticians can help. However, these must be individually adapted and cost between 150 and 200 euros extra, depending on the version. Since the otoplastics have to match the in-ears, interested parties should find out about the possible model combinations in advance.

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