Actually, it is the electric current sound existing in all good machines. Generally, the higher the power, the greater the static sound.
√ Turning on after put it in ears, then turn up the sound gradually. Generally, You will get used to it after 2-3 weeks.
2) What causes the feedback?
If the ear dome is not inserted well into ear canal or air leaks at the ear dome edges, when the device is close to hand or wall, a certain amount of sound will go back into the microphone. The sound is re-amplified which causes that annoying whistle.
√ Try and select suitable ear dome. Put the ear dome into the ear canal and make sure it fits snugly inside.
3) Can’t Charge Normally？
√Slightly adjust the position of hearing aids for a perfect connection.
√The projector light turns red when it is connected well; the light turns green when it is fully charged.