Many hearing aids now have directional microphones. These can be a major improvement in areas with a lot of background noise, like restaurants and public spaces. The directional microphone allows the user to focus on the sound source they wish to listen to, and to reduce amplification of conversations behind and to the sides. It is common for such a hearing aid to have both a directional microphone and conventional microphone. Thus user can switch between them as the situation warrants.
Modern digital signal processing has allowed hearing aid designers to develop devices that can actively reduce background noise. These require a fairly significant level of processing, and techniques are continuously being developed in order to increase the effectiveness of the hearing aid. While it is desirable to increase the signal to noise ratio, it is often hard to discriminate the desired sound from the background noise.
Digitally programmable hearing aids can be programmed to have a variable frequency response. They can also be setup to have a series of different settings that are appropriate for different situations and levels of background noise. The user can switch between the different settings as needed.
While telecoils have been available for some time, more hearing aids are being developed with a direct audio input, or DAI. This allows the hearing aid to be connected to an external audio source like a CD player or television. This is preferred by many over a telecoil, as there is less interference. DAI is usually available only in behind the ear hearing aids. They usually use a wire to connect the hearing aid to the external source.
Recent advances in hearing aid technology include the use of wireless technology. This would have the same purpose as direct audio input, without the wires. A person with a wireless hearing aid would also have an FM transmitter that they could hook up to the television, or to a clip on microphone that could be given to someone they wish to have a conversation with.