Microphone Technology Directional or dual microphones can improve speech understanding in some noisy situations. These microphones favor sound entering the hearing aid from the front and provide some attenuation to sound coming from the rear or the side of the listener. In most communication situations, the talker is positioned in front of the listener, while competing noise comes from the rear or side. In such situations, the speech entering the directional or dual microphone system is louder than the environmental noise. If noise and speech come from the same direction, however, the directional or dual microphone loses its advantage.
Directional microphones have some disadvantages.
First, they do not attenuate high frequency sound coming from the rear very well. Therefore, they are not effective with high frequency noise. Second, important sound coming from the rear may be attenuated too much. Some hearing aid users prefer to use directional microphones in noise and omnidirectional microphones, which pick up sound from all directions equally well, in quiet areas. Most directional hearing aids do not allow consumers to switch from one mode to another.