In an ideal world, hearing aids measure the sound environment, highlight the sound you want to hear and bring it to you with increased clarity. In most cases, hearing aids do this well. However, at times, you may wish to adjust the hearing aid sound for the environment you are in. You may want to appreciate the nuances of music, hear the person who is speaking from behind you, like in a car; or understand better in a particularly reverberant (echoey) room.
In these cases, you may want to change the way the hearing aids are working; adjust the volume or focus on sound in a particular direction. These are the situations where a remote-control app may come in handy. Apps usually give you the option to change your hearing aid volume, program setting and, in some cases, pitch and adjust how the hearing aids respond in noise.