Sennheiser CX 400BT TWS Earphone Review – German Co. With Chinese Voice Prompts?
Stripped down version of the venerated MTW (no ANC, no waterproofing), the Sennheiser CX 400BT looked and felt a bit overpriced at its original $200 SRP but merits consideration at the current <$100 street price.
Square, protruding buds are light but large size may compromise comfort for some; passive isolation is only fair but call quality is good. As with most such mainstream products, volume seems limited, and these CX 400BT need to be cranked near the max.
Tip sensitive—foams enhance bass but deaden the high end while biflanges or narrow bore silicons show more detail at the expense of subbass depth. Accompanying app is minimalist but functional. Touch controls work better than most.
At least from memory, the CX 400BT sound a great deal like the MTW II—warm, somewhat laid-back and L-shaped with a bit of midbass boost. Soundstage is fairly narrow and is somewhat limited in height but imaging and layering are outstanding—you can place the position of each performer precisely. Very coherent; subbass has pretty good depth and rumble while midbass isn’t super-sculpted but avoids bloom.
Treble isn’t as detailed or sparkly as class-leaders like the Klipsch T5 II—there’s some smoothing of the highest frequencies—but these avoid sterility and do a good job with lower-quality files. The Cambridge Melomania has more midrange presence and sounds truer-to-source, though the CX-= 400BT has cleaner stereo spread and otherwise shares the Melomania’s mellow, analogue tonality—you can listen for hours without fatigue.
Ultimately, the CX 400BT occupy a strange place in the middle of the TWS universe—they’re not particularly well-designed or featured and aren’t optimal for the gym or the subway, while cheaper favorites like the Soundpeats H1 have a more energetic, fist-pumping (albeit less natural-sounding) presentation.
However, Sennheiser does know how to tune an IEM, and if you’re going to use them indoors and sound quality is your priority, the CX 400BT outguns mainstream peers like Sony/Samsung/Beats.
Non-disclaimer: bought ‘em “Renewed” on Amazon for $69, which registers as a good buy.