Of course no definitive diagnosis can be arrived at without expert examination of the ear and associated structures.
However, it has been documented that a diver may have a very small perforation of the ear drum, so small that it does not preclude equalization or allow water to enter the middle ear space. Typically these do not cause any discomfort and can develop without an identifiable incident of trauma to the drum.
Following equalization on the surface, it is posssible for others to hear whistling, squeaking or "singing" sounds as air escapes the affected individual's middle ear.
This is educational only and does not constitute or imply a doctor-patient relationship. It is not medical advice to you or any other individual, and should not be construed as such.