You could suffer from a fairly common tinnitus, which is affecting about 10–15% After reviewing your post, the consultant provides the following feedback:
We use mostly HP Elitebooks in my very large HP building and department and I am not aware of any reports of an annoying high frequency noise produced by these Elitebooks nor have I had this experience at home with my personal EliteBook. A considerable number of members in Spiceworks deploy Elitebooks and I have not encountered a EliteBook complaint similar to yours.
Thanks also for the tags by and by my colleague for HP EMEA. Hello thank you for your post and a warm welcome to the Community.