Design and features:The CX 350BT has a integrated microphone, and volume, music player, and call connect/disconnect controls for paired Bluetooth devices. Additional features include support for Google Assistant, Apple Siri, and other digital voice assistants when used with Bluetooth connected devices that have those features. This model comes with four pairs of ear pieces in various sizes and a USB charging cable. The free Sennheiser Smart Control app download for Apple and Android mobile devices can be used to change the earphone's tonal balance with tonal presets and graphic EQ adjustments, and to update the earphone's firmware.
Sound quality: We found the CX 350BT delivers sound quality that falls in the very good range - it reproduces music and voice very well although it does have some noticeable sonic quirks. The bass (as in bass drums, bass guitars, stand-up bass, etc.) has good impact and goes fairly deep, but is a bit boomy. The midrange (voices, guitars, horns, etc.) is fairly even but a touch hazy and etched (a bit more sharply outlined then it should be), and a bit grainy. The treble (cymbals, the upper range of violins, etc.) is extended, but a bit prominent and a touch smeared. The sound also has a good sense of liveliness and is somewhat open--sound-wise it almost seems like you don't have anything plugging up your earr and it does a good job of recovering room ambience (the sense of the acoustic space in which the audio program that's being listened to was recorded). Mixed character - warmish bass with a neutral midrange and treble. The overall sound can best be summarized as fairly even but the midrange is a bit lean.
Comfort: As typical of in-ear models they produce a sense of pressure in the ear canal opening that might be uncomfortable for some. Fits and stays in place with no problem for casual use for users with small, medium, and large sized ear canals, but the cable may get caught on clothing and may pull the earphones out of the ears. The sound of the earphone connecting cable rubbing on clothing may be heard through the earphones by some users depending on the clothing it's rubbing on.
