Sennheiser CX Plus SE True Wireless (Black) review

What the CX Plus SE is—and what the suffix means

The U.S. CX Plus SE True Wireless is a complete pair of sealed in-ear Bluetooth earbuds, not an earbud accessory or a cable-linked neckband. Sennheiser identifies this Black version as article 509247, its sole listed default product variant, and marks the item end of life on its own U.S. store. The launch description calls SE a Special Design Edition and identifies its visible distinction as a brushed-matte surface on the earbuds. The maker’s manual lists both CX Plus SE and CX Plus True Wireless under the same CXPLUSTW1 earbud-and-case family; the documents checked here do not establish a separate SE-only audio function. The appearance image is a reference to the matte-black earbuds, not proof of a complete seller package, condition or current availability.

This is a source-based assessment of Sennheiser’s model page, shared family manual and official support FAQ, not a hands-on test. Its clear appeal is an older sealed-tip model with ANC, transparency, a choice of common codecs and independently usable left or right earbuds. Its boundaries matter just as much: only one source device can be connected for playback at a time; the eight-hour runtime example is explicitly with ANC off; the case is USB-C wired only and not splash resistant; and the U.S. maker page says the model is end of life.

Tip fit shapes the listening experience

The shared CX Plus manual describes ear-canal coupling and lists four silicone adapter sizes—XS, S, M and L. A properly selected tip can contribute to passive isolation and the seal on which active noise reduction works, but four sizes do not predict a personal fit. Ear shape, insertion, pressure and stability vary. Before treating this form factor as comfortable for a long commute or exercise session, check the exact package for the sizes you need and use a seller’s return terms rather than relying on a generic “ergonomic” claim.

The CX Plus SE combines that seal with electronic ANC and a Transparent Hearing mode. Sennheiser describes the mode as letting outside sound back in without removing the earbuds. This can make the design more adaptable than a no-ANC model, but it is not equivalent to an open-ear design: these tips still sit in the canal, and changing the electronic mode does not establish that you can hear every warning or conversation. The maker warns that ANC can reduce awareness of ambient sound, so local surroundings still matter.

Do not turn the battery claim into an ANC promise

Sennheiser’s shared manual gives about eight hours from a fully charged earbud and about 24 hours using the case, but its condition line specifies AAC, an iPhone within one metre, volume at 50%, Transparency Mode off, ANC off and no EQ settings. The manual does not state a separate ANC-on music runtime. That difference is decisive if you are buying for a fixed ANC commute: this review does not treat the eight-hour off-mode example as ANC endurance, nor does the finder count an undocumented ANC runtime as satisfying a numeric minimum. Volume, connection, settings and age also affect real use; the capacity of a second-hand battery cannot be inferred from the original maximum.

The instructions document USB-C cable charging for the case, and the official family FAQ explicitly says there is no wireless charging. A short USB-C-to-USB-A cable appears in the manual’s package list, but that list does not prove what an individual resale offer includes. Check that the exact case is supplied and charges, that both earbuds connect and charge, and that the cable and tips you need are actually in the box. The family FAQ also says the battery cells are not exchangeable, another reason to ask about an older unit’s condition and return window.

Codec choice is not device compatibility

The manual lists Bluetooth 5.2 and SBC, AAC, aptX and aptX Adaptive. The source phone, tablet or computer decides which supported codec can be negotiated, so a codec printed in a product specification does not guarantee that your host or app will use it. For the finder’s AAC or SBC requirements, the official list supports those paths; an aptX-focused setup should be checked against the manual and the exact transmitting device rather than inferred from a general “high-resolution” label.

The CX Plus family can remember up to six paired devices, but remembering is not Multipoint. Sennheiser says playback can come from only one device at a time and its FAQ explicitly answers that two devices cannot remain connected simultaneously. Expect to disconnect or switch manually when moving between work laptop and phone. In contrast, either the left or right earbud may be used alone, which is a different flexibility: it concerns using one side, not using two source devices at once.

Water protection applies to the earbuds, not the case

The exact SE page and family manual document IPX4 splash resistance for the earbuds. The instructions warn against immersion, shower use and charging wet earbuds; the official FAQ states that the charging case is not splash resistant. Do not transfer the earbud rating to the case or treat IPX4 as waterproofing. If a workout or rainy walk is part of your routine, dry the earbuds before placing them in a dry case, and do not assume the case can share the same exposure.

Who might still consider this earlier model?

The CX Plus SE can remain a sensible item to identify if you specifically want a brushed-matte Black CX Plus, sealed silicone-tip fit, ANC and transparency, an IPX4 earbud rating, and USB-C rather than wireless case charging. It is a poor fit for someone who needs two simultaneous source connections, wireless charging, a water-rated case or a documented minimum ANC playback duration. Compared with the separately reviewed CX 400 BT, the SE adds supported ANC and an IPX4 earbud rating, while retaining a one-source limit; neither family’s maker-page end-of-life notice tells you whether a particular retailer has a new or used offer.

Before considering any listing, match the name and U.S. article 509247, verify that the offer is a complete set with the compatible case and tips, ask about battery and charging behavior, and read the warranty and return terms. Do not confuse it with standard CX Plus True Wireless article 509188, the older CX True Wireless or the CX 400 BT simply because their names overlap. No individual offer, seller, price, stock, remaining battery capacity or customer experience is assessed here.