Sennheiser CX 150BT

These in-ears are impeccably crafted and feature a particularly neat casing that fits completely into the ear making for a very discreet appearance. In fact, they can easily be worn under a hat if required. In spite of their low profile, there is enough stability for moderate running and physical activity. The low weight of 15 grams means that no issues arose from unpleasant pressure in the ears, even during prolonged use. However, annoying cable noises caused by contact with clothing can be perceived.

The running time is impressive for such a lightweight pair of headphones, with up to 15 hours at a slightly raised volume level. If the battery is completely empty, recharging via the USB-C port takes almost exactly 105 minutes. This can be done with the USB-C to USB-A charging cable, which is included in the accessories. The CX 150BT are also supported by the free Sennheiser Smart Control App, but at the moment the app seems to be due an upgrade, as only a function overview and access to the headphone operating instructions were available. However, on the plus side, there is the option to update the firmware via the app.

Device control

In an urban environment, these Bluetooth headphones, in combination with various Android and iOS devices, offered ranges of a good eight metres. The wireless connection proved to be extremely stable and free of dropouts. There were no connection problems, with pairing taking place by holding down the central remote button. This switches the system on and puts it into pairing mode. The same button is then used to control playback and to answer and end telephone calls, which can be made with good speech intelligibility. Double-clicking allows you to skip forward to the next track and pressing the button three times allows you to skip back to the previous track. For volume control, however, separate plus and minus buttons are available.

Sound

The CX 150BT sounds pleasantly balanced, very natural and clear. I especially liked the voice and bass reproduction. Although the bass foundation reached quite deep and had power, it didn’t seem superficial or overloaded, nor was it too thin. Furthermore, the low frequency range was well defined. Vocals were even more precise and were reproduced with astonishing clarity; they didn’t appear thin, neither were they obtrusive. These qualities benefited both audio books and movies, where the very authentic and realistic voice reproduction comes into its own. Another positive aspect is that these headphones have a sound stage that appears quite open and spacious for an in-ear system. In my opinion, only the well-balanced trebles don’t draw with same exactness and they lacked a bit of precision. But that’s some high level pickiness as these headphones offer extremely good sound quality considering their price range. Support for the aptX audio codec would have been nice, as it is, Android users have to make do with the SBC standard, but in conjunction with Apple devices, the higher quality AAC format can be used.