Sennheiser CX Plus True Wireless

The Sennheiser CX Plus True Wireless are reminiscent of the CX 400BT and are available in black or white. With IPX4 certification, the device we tested was certainly suitable for sports use.

Technically, the CX True Wireless and CX Plus True Wireless are closely related. Both use touch-sensitive surfaces on the outside of the earphones and the free “Smart Control” app for iOS and Android. This offers comprehensive function control and configuration as well as the option of firmware updates (as of 1.8.19). A graphic equaliser is also available. In addition to the features of the standard model, noise-cancelling functions and the transparency mode have been added. Two microphones are installed on each side for this purpose.

Design and wearing comfort

The charging case and these exceptionally lightweight earpieces (6 grams) are made of plastic. This is robust enough for everyday use. The shape of the earpieces seems slightly chunky, and they protrude slightly from the ears. However, wearing comfort is pleasant thanks to ergonomic driver housings and a choice of four silicone fittings. As a result, the Sennheiser CX Plus True Wireless fit securely and without pressure in the ear. The outer insulation is good in both directions.

Battery life of the Sennheiser CX Plus True Wireless

Sennheiser quotes the runtime as eight hours plus a further 16 hours via charging in the case (approx. 420 mAh). However, this value is only achieved with noise-cancelling switched off. In principle, the playing time is practical enough for everyday use. The charging time for the case via USB-C is about one and a half hours and it is indicated by multi-coloured LEDs. Fast charging cycles are supported, as is inductive case charging (it is Qi-compatible).

Operation

The wireless link for the Sennheiser CX Plus True Wireless works with the latest Bluetooth 5.2 and, in practice, proved to be stable and usable across several rooms. The triggering of the touch functions also works well but produces a pressure noise in the ear. As with most of their competitors, this occasionally leads to errors. It is possible to use single, double and triple clicks on each side. Besides pairing, there are functions for music playback, track skipping, volume control, handling calls and summoning a voice assistant (Siri/Google Assistant) on your smartphone. The transparency function and noise cancelling are also selectable.

The earpieces can be used individually if required. They are switched on by removing them from the charging case and switched off by placing them back inside. It is also possible to define a time period after which the headphones automatic switch off when not in use. You can also activate automatic call acceptance when the right earpiece is removed from the charging case.

Unlike the CX True Wireless, the CX Plus True Wireless have mastered the auto-pause function. Music playback is paused when an earphone is removed from the ear and resumed when it is inserted. In other words, you really have full control.

Smart Control for Apple iOS and Google Android

You can make numerous configurations via the attractive app: Status information can be confirmed with tones and multilingual announcements, and fortunately, it can also be completely switched off. These button assignments can even be individually assigned or completely deactivated for the CX Plus True Wireless. I also liked how it displayed the codec currently in use.

They’ve not forgotten about individual sound adjustment either. The app offers a three-band equaliser in two views. In addition to ready-made pre-sets, there is also the option of saving your own settings.

Noise cancelling of the Sennheiser CX Plus True Wireless

The Sennheiser CX Plus True Wireless’s noise cancelling works with one external microphone at a time and can only be switched on or off. However, it packs a punch, resulting in a significantly quiet room. This reduces the signal-to-noise ratio when listening to music and provides additional silence in mobile mode or in the office. The usual static and low-frequency noises are effectively suppressed. Voices also fade into the background, while higher-frequency, sudden noises such as keyboard clacking remain audible. I would rate the performance very positively for this price range and in view of the low premium compared to the standard CX True Wireless model. Although it would have been nice to able to adjust the degree of isolation.

There is room for improvement in the status of noise cancelling during start-up. Here, the app (in iOS) always shows inactive noise cancelling, however, it can quickly be activated via touch function.

Transparent mode

With the switchable Transparent Hearing function, you can bring outside noises back into play or into the ear. This serves to improve the perception of your environment as well as improving communication and it functions in a practical way. One nice feature is the switchable automatic function, which interrupts (and resumes) the ongoing music playback.

Sound

Considering their price class, the Sennheiser CX Plus True Wireless have no weaknesses in terms of sound. The device we tested supports audio codecs SBC, AAC, aptX and the newer 24-bit aptX Adaptive. The same dynamic 7 mm drivers are used as in the CX True Wireless model. They provided a well-balanced, powerful sound with sufficient level reserves and a degree of bass emphasis. The tuning is full-bodied, but the CX Plus True Wireless maintain sufficient precision and deliver the necessary dynamic and tonal information. The level reserves were quite adequate, though one should not overdo it with bass-heavy material.

A certain warmth can also be found in the mid frequencies: voices and instruments of all kinds were reproduced just as credibly in emphatically clean mixes as they were in complex ones. Even distorted guitars and metal productions sounded coherent. This makes it easy to distinguish the quality of a production.

In the treble, the Sennheiser CX Plus True Wireless deliver the necessary sparkle, transients, details and spatial information. Audiophile airiness should not be expected, but neither does it sound harsh nor too muffled. The tuning simply shows Sennheiser’s many years of experience as a headphone manufacturer.

The equaliser makes it possible to vary this favourable tuning according to taste, for example to lower the bass discreetly. The additional “Bass Boost” button hidden in this area of the app, was slightly confusing but fortunately it does not intervene too boldly in the sound.

Last but not least, the CX Plus True Wireless create a broad and stable stereo panorama in which sound sources can be easily located, both statically and in motion. Reverberation effects are comprehensible, while graduation into spatial depth is rather less pronounced.

These results recommend CX Plus True Wireless for use across genres, but especially for modern pop and rock music. However, you can also enjoy classical and jazz music if you do not approach it with explicitly audiophile demands. Of course, one should always keep in mind the attractively low price of just under 160 euros, which is almost half of the Momentum True Wireless 2.

Talking on the phone with the CX Plus True Wireless

Speech intelligibility during phone calls was ultimately quite good and noise-free. There are three levels of adjustment to determine whether the user’s own voice is transmitted to the driver in order to achieve a more natural call quality (sidetone). In addition, you can decide whether the transparency function is active during telephone calls. This can help to better perceive voices and, if necessary, include ambient noise. However, the exaggerated spatial effect can be a bit disturbing.