I bought these earbuds 10 days ago and I noticed immediately this weird sound issue. The issue is already common for many people and it seems that it affects sometimes the left and sometimes the right earbud. 

In my case, I can hear a ringing or pinging noise coming from my left earbud whenever I'm in a call and someone is speaking, including me. It follows the higher notes of the voice and kinda sounds like an echo but a similar sound to the notification sound you have when you tap on the earbud to either change the NC on or off or to play or pause the music. What I noticed is that the issue can be reproduced also if I snap the left part of the teeth quickly.

If I turn off the NC, then I can't reproduce the issue when snapping my teeth but it still can be reproduced if someone talks in a voice call. Also, I can just listen to a podcast, and no matter if NC is on or off, the pinging is there. It just seems that if NC is off that the issue is less obvious. But again this is in my case, other people have the same issue but reproduce it a bit differently. These are the Reddit posts I found that reference the same issue:


https://www.reddit.com/r/sony/comments/obsdne/wf1000xm4_faint_pinging_noise_during_voice_calls/
https://www.reddit.com/r/sony/comments/ot5vqf/wf1000xm4_anyone_not_having_metal_sound/
https://www.reddit.com/r/sony/comments/oa0oy3/sony_wf1000xm4_hollow_ringingpinging_in_left_ear/
https://www.reddit.com/r/SonyHeadphones/comments/o1ah8m/tinnymetallic_noise_when_listening_to_speech...

Can anyone confirm if this is a design flaw with the hardware or some weird issue with the ANC and microphones that can be resolved with a future update?