Sennheiser CX 150BT (Black) review

This assessment covers the U.S. Black CX 150BT, article 508380, and its same-family White finish, 508381. Sennheiser's U.S. page now marks the model end-of-life. The review is based on that listing and the model manual, not listening, fit, call, battery or water testing. An older unit's remaining capacity and seller-specific condition are unknown.

A Bluetooth neckband, not a true-wireless set

The CX 150BT is a pair of sealed, tip-style earbuds joined by a cable that rests around the neck. That makes it materially different from fully separate true-wireless earbuds: the wire can keep the two sides connected to one another, while the built-in electronics and battery sit on the cable. The manual calls the fit an ear-canal coupling and includes four silicone adapter sizes, XS through L. It says the tips should sit snugly and seal the ear canal. Those instructions establish the design, not whether it will feel comfortable or stay secure for a particular person.

There is no active noise cancellation feature documented for this model. A well-fitted tip can create passive isolation, but that is not an ANC system and the manual's advice to keep the product dry is not a water-resistance rating. If ANC or a stated splash rating is a firm requirement, this model's documentation does not support either one. The neckband is also a poor match for someone who specifically wants buds and case with no connecting cable.

Two codecs, with the phone still in the loop

The CX 150BT's manual lists Bluetooth 5.0, SBC and AAC. Those are supported Bluetooth audio codecs, not a guarantee that a phone or computer will choose AAC: the source device, software and settings determine the negotiated route. There is no aptX or aptX Low Latency codec listed for this model. Its omnidirectional MEMS microphone and call controls make phone calls part of the documented use, but the available sources do not provide a real-world call-quality test.

The inline remote has volume-up, multifunction and volume-down controls. The product page describes the CX 150BT as a three-button design; the manual also documents track and call functions. The free Smart Control app is a companion for settings and product information, rather than a requirement for basic Bluetooth audio. Users who want an equalizer or codec option beyond SBC/AAC should compare another model rather than assume the app adds a missing codec.

Multipoint and pairing memory are not the same number

Sennheiser's U.S. description advertises multi-connectivity with two devices at once. The manual says the headset can store up to eight pairing profiles and, on startup, tries to reconnect to the last two connected devices. That is useful for a phone-and-computer routine, but it does not mean that two audio streams play at the same time; output still comes from the selected active source. The number eight is remembered devices, not eight simultaneous connections.

For conservative matching, the codec-specific plans and the two-device connection plan are kept separate: the documentation lists the codecs and two-device capability but does not state that a particular codec's behavior or runtime is measured while both sources remain connected. A listener who needs a documented SBC or AAC route can match those plans; a shopper who needs simultaneous device connections can inspect the separate multipoint plan. Do not read either statement as proof that every host switches seamlessly.

Ten hours is an SBC maximum, not a case total

The model manual specifies up to 10 hours of music playback via SBC, from its built-in 100 mAh rechargeable battery. It lists about 1.5 hours to charge and 340 hours in standby. Standby is not listening time, and the ten-hour figure is a manufacturer specification rather than an independently measured result. No ANC-on runtime applies because the CX 150BT has no ANC, and no charging-case total applies because there is no case.

The unit charges directly through USB-C. The manual's package list includes a USB-C-to-USB-A cable, but says the USB power source is ordered separately. That distinction matters when checking a used listing: the photo of the headphones is not proof that the cable or printed guides remain in the box. Since the U.S. page calls the model end-of-life, battery aging and completeness are offer-specific questions, not facts this assessment can settle.

How the CX 350BT differs

The CX 350BT shares the neckband-and-sealed-tip format, two-device connectivity, Bluetooth 5.0 and a ten-hour SBC playback specification. Its manual adds aptX and aptX Low Latency to SBC/AAC, and its control housing has a dedicated voice-assistant button. The tradeoff is a longer listed full charge of about 2.5 hours versus about 1.5 hours for the CX 150BT. aptX Low Latency is relevant only when the source also supports it; it is not a universal latency fix. These differences make the 350BT the better-documented match for a compatible aptX or voice-assistant-button preference, while the 150BT remains a simpler SBC/AAC option.

Exact finish and older-offer checks

The U.S. selector maps Black 508380 to one finish and White 508381 to the other. The checked sources disclose no functional difference between those colors, so the White row shares this assessment but retains its own exact image below. The images are manufacturer appearance references only: they do not show the complete retail package, the condition of a used battery or current stock.

Consider the CX 150BT only if a cable-linked, sealed-tip Bluetooth design and no ANC fit the brief. Before considering any older offer, match the exact finish and article number, check the cable and ear-tip package, and ask about battery condition, returns and seller warranty. None of those offer-level details was checked here.