Sennheiser MOMENTUM True Wireless (Black 508524, first generation) review

This source-based assessment covers the U.S. Black Sennheiser MOMENTUM True Wireless, first generation, support model M3IETW, article 508524. Sennheiser's U.S. page now calls this model end of life. The information below describes the manufacturer's documentation; no listening, fit, call, battery or cancellation test was performed, and the condition of any current seller's unit is unknown.

Identify the unnumbered first generation

The U.S. product record names MOMENTUM True Wireless and lists one Default Title configuration, SKU 508524. Sennheiser's spares record labels the same article M3IETW Black. This is the original unnumbered model, not MOMENTUM True Wireless 2, 3, 4 or the later True Wireless 5. Those names identify separate assessed models and have different documented functions. In particular, do not transfer a later generation's active noise cancellation, case-charging feature or runtime to article 508524.

The manufacturer's 2018 launch describes the product as the first truly wireless member of the MOMENTUM range. Its shell-based pair connects without a cable between the left and right earbuds; the fabric-wrapped case stores and charges them. The exact product image is a small manufacturer appearance reference of the Black pair in its case. It is not evidence that a seller's listing includes every part, the original carton or a working battery.

Sealed tips with a separate ambient-sound mode

Sennheiser's manual classifies the earpieces as ear-canal-coupling and includes silicone adapters in XS, S, M and L. It directs the wearer to insert at a slight angle and twist a little for a snug canal fit. That supports a sealed-in-ear description, but neither the size list nor the fitting instructions predict a seal, comfort or retention in a particular ear. A return window matters if tip fit is a deciding factor.

The model documents Transparent Hearing: its microphones can pass ambient sound through while the earbuds remain in place, and the Smart Control app provides settings for how that mode works. Transparent Hearing is not active noise cancellation. The original model's sources do not document an ANC mode; passive attenuation from a well-fitting tip should not be treated as ANC or as a substitute for a model that has it. The guide and product description also mention touch controls and voice-assistant access, but these features do not change the fit or cancellation boundary.

Classic Audio codecs depend on the host

The M3IETW manual lists SBC, AAC, aptX and aptX Low Latency. The manufacturer says a compatible source can select its supported higher-quality codec; otherwise playback uses SBC. That list is a capability of the earbuds, not a promise that every phone, computer, operating system or app will negotiate a particular codec. Check the source device and the settings you actually use.

The manual says the earbuds can save up to eight Bluetooth profiles and automatically try the last connected Bluetooth device at startup. Its diagram shows one connected source, with other paired devices not connected; disconnecting one device leads the earbuds to search for another saved device. That is not documentation of Multipoint. Eight remembered pairings should not be mistaken for two simultaneous hosts, and a two-device requirement is not established for this model.

Four hours is general playback, not ANC runtime

Sennheiser's manual gives approximately four hours of operating time from fully charged earbuds, plus approximately eight hours of recharging through the case, up to two additional charging cycles. Its launch material also describes a four-hour battery figure extended to up to twelve hours through the case. Treat these as manufacturer claims for a new unit, not a hands-on result or a forecast for an older battery. Case-assisted time is not one uninterrupted earbud session; the available documents do not assign the four-hour figure to a specific codec, volume or laboratory protocol.

There is no ANC mode in the documented operating arrangement, so no ANC-on runtime is established. A high ordinary-playback maximum cannot satisfy a numeric request for ANC hours. This is especially important when comparing the original with the separate MOMENTUM True Wireless 5 assessment: shared naming does not make their ANC or runtime specifications interchangeable.

USB-C case, earbud-only IPX4 and an older service path

The manual identifies a USB-C input on the case and includes a short USB-A-to-USB-C lead. It does not document Qi charging or a wireless-charging contact area for the original M3IETW case. This is a wired-only assessment of article 508524, not a claim about later MOMENTUM True Wireless cases. The manual assigns splash-proof IPX4 to the earbuds only; it does not assign an IP water rating to the charging case. Do not extend the earbuds' rating to the case, submerge the product or charge it wet.

The exact U.S. product page labels the model end of life, and Sennheiser's service page says non-warranty service is unavailable for this item. That does not establish that every independent repair is impossible, but it is relevant when evaluating an older offer. Ask for a photo of both earbuds, the M3IETW C case, the USB-C cable and available tip sizes; verify that the set charges and pairs, and review the seller's condition, warranty and return terms. None of those offer-specific facts has been checked here.

Primary sources: Sennheiser's exact U.S. article 508524 product page, its M3IETW instruction manual, the article 508524 service and spares record, and the 2018 manufacturer launch description. The manual was read in Sennheiser's document reader; the direct PDF byte request returned HTTP 404, so no local manual hash is claimed.