Bone conduction (actually quite precisely: bone conduction transducer, because bones don’t usually make sound) is the rather creepy term for the – pleasing to music lovers – a phenomenon that sound vibrations can be perceived not only with the eardrum but also with transmission through the body (to the cochlea).
The market leader in this field is the company Aftershokz, which uses this principle in its entire product portfolio. There are good reasons for using a bone conduction technology because it offers a number of principle-related advantages (though also disadvantages, but more on that later). First of all, the ears remain free so that one remains in acoustic contact with one’s surroundings, and also the sometimes somewhat annoying pressing in your ear is eliminated. Waterproofing is also much easier to establish, as the drivers can be fully encapsulated – accordingly, the Aeropex tested here are waterproof to IP67. In addition, the whole thing is quite easy on the ears, since the eardrum is bypassed.
Enhanced by four colour variations (Cosmic Black, Lunar Grey, Eclipse Blue and Solar Red), the Aeropex are currently the top of the line in Aftershokz’s bone conduction earpiece range. They transmit with Bluetooth 5.0, mastering the profiles A2DP, AVRCP, HSP and HFP, and have a playing time of around eight hours after a full charging cycle of two hours. They also offer hands-free functionality and easy media/call control via a multi-function button in the left earpiece.
That the Aeropex are aimed at a sporty outdoor target market is made abundantly clear from the packaging, which features pictures of urban sporty people. The fact that the bone conduction transducers are won’t even mind if you’re taking part in a full-on cross-triathlon becomes apparent as soon as you take the extremely flexible earpiece, which is made of one piece and covered with rubberised plastic, out of the packaging. There is nothing sharp-edged about it and no rigid spot where something could break. Weighing just 26 grams, if you drop it, nothing happens. So there’s no question about it: the Aeropex is a robust piece of equipment. It is charged via an included USB cable with a magnetic plug that slips onto the charging contacts on the underside of the right earpiece in the best MagSafe manner. What’s great about this is that the plug cannot be connected incorrectly with the strong magnetic polarisation and the charging circuit detects whether there is a short circuit due to moisture. If this is the case, the user is warned with an urgent flashing light and a beep.
Switching on and off, pairing and volume is controlled via two buttons on the right side of the headphones. On the left, there is an almost invisible multi-function button that can be used to pause, forward/back, answer/end/reject and voice dialling via various touch variations. Connecting via Bluetooth and the stability of the wireless link was not a problem in our test. SBC is used as the codec.
Putting on the Aeropex is as easy as can be: you simply place the headband over your ears, whereupon the two induction ends almost automatically rest on the skull bone a little below the temples. The wearing comfort is correspondingly fantastic: you hardly notice the presence of the headphones and they can also withstand violent head movements without complaint due to their low mass. Nevertheless, due to the shape of the earpiece, you notice immediately if you lose it – very good. Spectacle wearers have to “stack” a little here, but that’s okay. In principle, the ears always remain free, so that you can perceive outside noises as normal, which is really great for phone calls, because here – unlike with ear-closing in-ears – you retain full control over your own voice in the room. Due to the good voice quality in both directions and the very comfortable fit on the head, I give the Aeropex a separate recommendation as a hands-free headset, regardless of their properties for listening to music. In case you don’t want to be disturbed by ambient noise while talking on the phone or listening to music, Aftershokz includes a separate pair of standard foam earplugs with the headset. Although this seems a bit – well – cheap, it works well in principle. However, the sound changes dramatically, and I would like to discuss this below.
What does it sound like when the sound does not reach the eardrum but comes in via the skull bones? Well – to put it briefly: rather thin. Even though Aftershokz describe the frequency response as 20 Hz to 20 kHz and I was able to determine at least a functional range between 60 Hz and 14,000 Hz in our test, what arrives in the ear, in the end, seems very narrowly limited to the mid-range in terms of frequency. A bit like a small medium-wave radio in your head. That’s not bad for phone calls, listening to podcasts or soft background chatter. If you turn up the volume, an unpleasant vibration at the temples sets in – a bit like from an electric toothbrush, which is why you automatically set the listening volume in the lower range. However, the effect is astonishing when you put the supplied earplugs in your ears, because then suddenly the pressure builds up in your ears like that you will be familiar with from in-ears, and you can even hear the bass. However, this obviously affects the treble reproduction, so that the sound image sounds unnaturally dull.
There is no question that the listening experience when wearing the Aftershokz Aeropex for the first time is quite spectacular. The sound is indeed “in your head” and this despite the fact that you can still hear the outside world unchanged and, due to the extremely robust and slim design, you don’t feel like you have anything in or on your ears at all. The richness of sound that travels through the bones into the ear, however, is rather limited to the mid-range and cannot compete with classic over-ear or in-ear designs in terms of loudness and frequency response. Speech, on the other hand, such as in podcasts, audiobooks, or telephone calls, is transmitted quite well by these earphones. In combination with the extraordinary feeling of freedom of the ears and the good speech quality, the Aeropex is recommended as an excellent lightweight headset for makers of frequent calls.
- Ear couplingBone conduction
- Frequency response (headphones)20 - 20.000 Hz
- Sound pressure level (SPL)±3dB: 105 dB
- Weight without cable26 g
What's in the box
- 2 magnetic charging cables
- Silicone bag
- available in black, grey, blue and red
- BT codecs: SBC
- BT version: 5.0
- BT profiles: A2DP, AVRCP, HSP, HFP