Externally, the HD350BT looks a lot like its more expensive brother. Both are even on par when it comes to sound - which pleases with a crisp and detailed character. Unlike the HD450BT, however, the 350 lacks active noise cancellation and a jack socket. In the remaining test points, it left just as good an impression. It is nice and light, and the battery lasts for 36 hours and 29 minutes.