Virtually all patients wearing hearing aids complain about background noise at one time or another. There is no way to completely eliminate background noise.
Background noise exists and is important to hear in order for the hearing aid user to be involved in their environment. There is no way to completely eliminate background noise, however, technology exists today to reduce distracting noise and allow you to focus better on the person you want to hear.
Remember, when you had normal hearing there were still times when background noise was a problem. It is no different now, even with properly fit hearing aids! The good news is there are circuits and features that help to reduce (or minimize) background noise and other unwanted sounds. In fact, there are research findings that demonstrate digital hearing aids with particular circuit and microphone options can effectively reduce background noises.
Many early digitally programmable (and even some digital) circuits, which claimed to reduce or eliminate background noise, actually filtered out low frequency sounds. This indeed made the sounds appear quieter, however, not only was the background noise made quieter, but so too, was the signal (the speech sound).
Newer ways to reduce background noise are based on timing and amplitude cues and other noise processing strategies, which 100% digital hearing aids can incorporate. These methods work, but are not perfect. Directional microphones are available and are useful as they help to focus the amplification in front of you, or towards the origin of the sound source. Directional hearing aids can offer a better signal-to-noise ratio in difficult listening situations by reducing a little bit of the noise from the sides or behind you. In most 100% digital hearing aids, the noise control features help make noise more tolerable, but do not completely eliminate the noise.
The best and most efficient way to eliminate or reduce background noise is through the use of FM technology.