They live dangerously - pedestrians and cyclists who are so loud with their wireless headphones that they do not notice much of their surroundings and meander through the turmoil of urban traffic as if remotely controlled.

Of course there is a remedy: Thanks to built-in microphones, many in-ear headphones can acoustically let through what is happening in the outside world.

And there is another way of maintaining contact with the smartphone and with real life at the same time: you entrust the playback of music to bone conduction headphones.

Bone conduction? The somewhat strange-sounding generic name indicates how the thing works. The ears remain free, the listener generates the tones with encapsulated transducers that sit just in front of the auricles, i.e. where the temporal bone meets the cheekbone. The cranial bone picks up the sound waves and transmits them to the inner ear; the hearing identifies them as an acoustic event. For choir directors and conductors, for example, this transmission method is part of their everyday routine: They like to press a struck tuning fork to their temple in order to hear the concert pitch loud and clear. And in medicine, bone conduction can help compensate for certain types of hearing loss.But what does the principle bring to the bike? And is it even suitable for ear-free remote communication via a headset in the office? We tried it with two new bone conduction headphones from Aftershokz, an American manufacturer that specializes in this type of transducer.

The model for cyclists, joggers and other fresh air activists is called Aeropex, costs around 170 euros and weighs 26 grams. A narrow, flexible titanium neckband holds the receiver securely on the head, even if the wearer is pedaling hard.

An all-round coating made of soft plastic protects the device from moisture.

The built-in battery should last up to eight hours;

It is charged via a USB cable that docks with a magnet on the handset electronics.

A directional microphone turns the headphones into an office headset

The radio connection to the smartphone works according to the latest Bluetooth version 5.0. To pair, press one of the two tiny volume buttons on the underside of the battery section for a few seconds; the smartphone then recognizes the handset model and can select it as a playing partner. The Bluetooth radio also supports telephoning; Pressing the multifunction button on the left transducer accepts the call, another press ends it, and two microphones on the right side of the listener capture the spoken word.

The second Aftershokz novelty is called Opencomm and is also available for 170 euros.

This model is more tailored to the world of work.

A small directional microphone on the swiveling bracket turns it into a headset for zoom conferences and other communication tasks.

The larger battery also fits this field of activity.

It is supposed to supply electricity for 16 hours.

You shouldn't expect musical brilliance

As a result, the Opencomm was a little heavier at 33 grams. Bluetooth 5.0 also provides the connection here, and pairing, i.e. establishing the connection to the smartphone or computer, works a little more elegantly. NFC, the radio for ultra-short distances, can take over as soon as the devices involved touch each other. Otherwise there are many similarities: Here, too, a titanium neckband ensures a stable hold, a coating defies moisture and dust, a multifunction button starts and ends calls or controls music playback.

Well, if you hold the transducers directly in front of your ears, their level is immediately noticeable. Headphones for the bone conduction have to play much louder than all other models that are aimed at the eardrum. Sometimes you can even feel their work on your skin. Powerful bass can tickle a bit. The bone transducers are good at medium frequencies, and their volume drops more and more towards the highest notes.

Musical brilliance is not one of the core competencies of this type of converter. The aftershokz listeners can reproduce speech quite well, and the Opencomm's microphone also makes a solid contribution to long-distance communication. The freedom from ears of these models is a delightful feature. In any case, in order to increase road safety for yourself and others, we recommend turning the volume down a little. This noticeably improves your own awareness.