Mar 15, 2018
Thanks for posting in the community!
The QC35II headset is designed to block out a lot of low frequency droning noises like the sounds of a cabin in a plane. We do try and block a lot of other frequencies, but there may be some leakage into the headset from higher pitch frequencies. Are you using these while playing music or just the noise cancellation? Have you also connected them to the Connect App and check what the noise cancellation level is?
Tony A - Community Support
Dec 15, 2016
Thanks for responding. I wanted to jump in here and add on to what Tony_A was mentioning. No combination of passive and active technologies reducing sound entering your ear can make sounds with higher-frequencies, particularly at voice frequencies, completely inaudible. We do have a post that talks more about ANC that you can see here.
Tony G - Community Support