Sennheiser HD 350BT

The ear cups tilt and swivel, as well as being foldable, making these Bluetooth headphones easy to transport, and they flexibly adapt to the shape of your head. The fit is not loose, but rather quite tight, making for a stable hold on the head even when on the move. Because the oval-shaped cups are angled, the luxurious leatherette upholstery fits snugly around the ears, helping to protect them from the outside world. However, the design does not offer much space which can lead to larger ears not being enclosed by the padding as intended; instead, it sits on top. Also, because of the rather tight fit, I would recommend these over-ears primarily for smaller to medium head shapes and ears.

In terms of energy, the handy size of these headphones offers a remarkable runtime of 45 hours at slightly raised levels, so that even long journeys are easy to handle. A full charge of the lithium polymer battery via USB-C connection takes a good two hours, a corresponding USB-C to USB-A charging cable is included with the accessories. However, the possibility of alternative wired use has been dispensed with, and there is no audio input available. The headphone’s usability via the free Sennheier Smart Control app also currently has room for improvement. One advantage is that there is the option of firmware updates and the EQ enables individual sound adjustments. However, these are rudimentary and cannot be saved, and there are no preconfigured presets to choose from. You do, however, have access to a function overview and the user manual.

Device control

Pairing the HD 350BT, which support Bluetooth standard 5.0 and multipoint connections with two devices simultaneously, is done by holding down the power button, which turns the system on and puts it in pairing mode. When used with various Android and iOS devices, there were no connection problems whatsoever, and the wireless connection proved to be extremely stable, particularly since ranges of up to 15 metres could be measured even within an urban environment. Top marks were also awarded for the speech intelligibility of telephone calls; they can be accepted and ended via the central remote using a movable button. This also controls playback at the touch of a button, while a vertical click is used to jump back and forward through tracks. However, for volume control and activating voice assistants, separate buttons are used. This has its disadvantages, as all controls and the USB-C connection are located on the lower right side of the ear cup. The buttons are small and quite close together, which at least to start with, makes orientation and operation difficult.

Sound

The HD 350BT are being advertised as having deep, dynamic bass, and this holds true. The well-rounded, slightly bouncy bass foundation has plenty of volume and considerable depth, which makes listening to bass-heavy music a lot of fun. At the same time, the low-frequency range does not appear overloaded, but compact, well defined and wonderfully agile. Very successful indeed! The mid-range reproduction is just as precise and with a pronounced clarity; vocals sound pleasantly lively and authentic, and movies and spoken content also benefit from this feature. In my opinion, the trebles seem to be tuned quite softly, which is an advantage for sensitive ears as even at high levels there is no biting or harsh sound. Nevertheless, the high-frequency range is present, even if there is a subtle fall-off. Overall, the price/sound ratio of these headphones is extremely good, especially since high-quality audio codecs are available for both iOS and Android devices. Also, the sound stage appears very clean and does not impart any feeling of narrowness, rather it provides a sense of spaciousness and openness.