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Sennheiser CX True Wireless review - Great-sounding in-ear headphones

Impressive audio. The Sennheiser CX True Wireless feature great sound quality and wearing comfort, promise a long battery life, and carry an IPX4 rating to boot. Is that enough to earn a recommendation?

The Sennheiser CX True Wireless in-ear headphones attempt to deliver great sound quality and incorporate the company's TrueResponse drivers, which, at least according to the data sheet, bear resemblance to those used in the Momentum True Wireless 2

The earbuds lack ANC and incorporate purely passive noise cancellation instead. Sennheiser's Transparent Hearing functionality is also not supported.  At the time of writing, the MSRP in Germany is 129 Euro ($129 in the US), although the price occasionally dips down into double-digit territory.


Wearing style in-ear
Connectivity Bluetooth 5.2
Driver dynamic TrueResponse driver, 7 mm, 5-21,000 Hz
Audio codecs SBC, AAC, aptX
Battery capacity (earphones) 60 mAh
Battery capacity (charging case) 400 mAh
Charging port USB-C
Wireless charging not supported
Weight (per earphone) 6.0 g
Weight (charging case) 49 g
Microphones 2 beamforming microphones per earbud, 100-10,000 Hz
Included in the box headphones, charging case, silicone ear pads (XS, S, M, L), USB cable, quick start guide
Price (MSRP) $129

Case and ergonomics - the CX True Wireless feature splash resistance

Both the charging case and the headphones are made out of matte black plastic, but the perceived quality is quite high nonetheless. The earbuds are held in place with magnets when resting inside their case and although they rattle slightly when shaken, they charge reliably. The lid's magnetic closure isn't particularly strong but still does its job. The charging contacts on the earphones themselves are recessed deeply enough to avoid contact with the skin.

In order to insert the earbuds into the ear canal, we had to use a slight twisting motion. Once inserted, they remained locked in place during vigorous physical activity and even headbanging. To ensure an optimal fit, Sennheiser includes four different sizes of silicone ear tips. If needed, replacement tips can be ordered cheaply directly from Sennheiser. The CX True Wireless is IPX4 certified and should be able to withstand splashing water and rain.

In addition to the headphones and the aforementioned silicon ear adapters, the box also includes a short USB cable (Type-A to Type-C; 28 cm / 11 in).

Features and operation - Sennheiser CX True Wireless with aptX support

With the CX True Wireless, Sennheiser is emphasizing sound quality above everything else and consequently, the earphones lack features like Transparent Hearing, Active Noise Cancellation, or wireless charging. The CX True Wireless supports the SBC, AAC, and aptX codecs, which is good news for those interested in high-resolution audio streaming. The headphones offer up to 9 hours of playback time, a claim we were able to substantiate during our testing as well.

Setup is simple and involves pairing the headphones with the respective smartphone, tablet or computer. Sennheiser's Smart Control App, which is available for Android and iOS/iPadOS, allows for a more granular configuration of the earbuds. You can control the earbuds via small touch panels, which are configurable in the Smart Control App according to your preferences. Using the app, the user can also tweak the integrated Equalizer and update the firmware.

Sound - TWS headphones with impressive sound

According to the data sheet, the Sennheiser CX True Wireless is equipped with comparatively compact 7 mm drivers, which provide an identical frequency response (5-21,000 Hz) as the transducers used in the Momentum True Wireless 2. To put it into context: the drivers of the Galaxy Buds2 are about 50 percent larger and measure 11 mm.

Size is obviously not everything and from an acoustic standpoint, the CX True Wireless play in a different league than the aforementioned Galaxy Buds2. The headphones are surprisingly powerful even down in the bass register and the overall sound is both balanced and accurate. What is missing is the last bit of airiness in the treble response - the Momentum 2 is better in that regard - but the CX True Wireless still sets the standard for the price range. Users desiring even more bass can dial in Bass Boost, which improves the lows, but muddles the mids and highs somewhat in our opinion. Of course, it all comes down to personal taste.

As impressive as the sound quality is, the performance of the microphones is a very different story. Even in quiet rooms, the CX True Wireless disappoints sorely when it comes to telephony or video conferencing. Our own voice comes across weak and somewhat choppy, with plenty of sound artifacts. Add some background noise to the mix and a conversation is next to impossible. When we found ourselves at a busy intersection, our conversation partner on the other end of the line didn't hear much aside from a cacophony of noise and clacking sounds.

Verdict - Great headphones, but subpar microphones

In review: Sennheiser CX True Wireless. Test sample provided by Sennheiser.
In review: Sennheiser CX True Wireless. Test sample provided by Sennheiser.

The CX True Wireless in-ear headphones are designed to deliver great sound quality and as far as that goal is concerned, they do set a new standard within their price bracket. Potential buyers interested in headset functionality need to look elsewhere, however. The integrated microphones are lackluster at best even in very quiet environments.

The Sennheiser CX True Wireless offer superb sound and a long battery life.

When it comes to the battery life, the True Wireless headphones from Wedemark once again impress with run times of nine ours per charge, even when using the high-resolution aptX codec. What's missing are goodies like Transparent Hearing, ANC, and the automatic ear detection - all features the Plus-version offers.

From a sound quality perspective, the Sennheiser CX True Wireless don't really have a direct competitor. Should telephony be on the agenda, however, Huawei's FreeBuds Pro might be an alternative.

Price and availability

In the US, the Sennheiser CX True Wireless can be purchased directly from the manufacturer at the MSRP of $129. Alternatively, you can also purchase the headphones at Amazon, although we haven't seen the price drop any lower.

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> Expert Reviews and News on Laptops, Smartphones and Tech Innovations > Reviews > Sennheiser CX True Wireless review - Great-sounding in-ear headphones
Daniel Schmidt, 2021-12-29 (Update: 2021-12-29)