Mass momentum

Borrowing key technology from the flagship Momentum ANC TWS has only helped the case of the more affordable passive version.

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The CX 400BT in-ears are modelled after the aforementioned flagship, using the same 7mm bespoke drivers that the Momentum’s have but come in a plastic case instead of a fabric-wrapped one and lose the aluminium end-caps, along with ANC. The passive seal is fantastic.

You can choose to wear just one master earbud if you wish to use them for a quick voice call rather than music but bear in mind, since these are on a budget, you don’t get the auto start/stop functionality on music when you remove any one of the buds.

Designed to block a high level of ambient sound through a passive seal, it creates an illusion of active noise cancellation quite convincingly. But, if you like more control over this aggressive “blocked-off” sensation, you might miss the transparency controls offered by ANC models. .

Sound quality is within spitting distance of big brother Momentum TW2’s and that is saying a lot considering those were probably the best true wireless in-ears we have ever heard. Tonal balance is perfectly judged with superb transient response and attack.

Unfortunately, the same passive seal that makes music come alive doesn’t work well with phone calls. Not being able to hear yourself clearly (or at natural volume) also isn’t the most comforting as you tend to speak louder than normal.

Tech specs

Driver 7mm

Frequency response 5Hz - 21kHz