The latest hearing aids are small and delicate. This makes them highly discreet. The housings are available in various colors. Water, sweat and dust-resistant models are available for athletes. There are even specially designed hearing aids for swimmers. These work down to a depth of one meter.
All hearing aids feature the same main components. A behind-the-ear hearing aid, for example, has the following functions:
- Microphone – Picks up sounds and converts them into electrical signals
- Amplifier – Increases the volume of the microphone signals and filters out irrelevant sounds
- "Loudspeaker“ – Converts electrical signals into acoustic signals
- Speech processor – Adjusts signals to the wearer's individual hearing needs
- Volume regulator – Lets the wearer control the volume
- Ear hook – Connects the hearing aid and the sound tube
- Audio input – Picks up signals from other external devices
- Disposable or rechargeable battery for the power supply – While disposable batteries can be changed several times, rechargeable batteries last for up to 24 hours with just one charge
The hearing aid is connected to the ear via a sound tube, which ends in a fixing piece, or earpiece/ear shell (earmold). A variation on the classic BTE hearing aid is the external receiver model (receiver-in-canal, or RIC
), in which the loudspeaker sits inside the ear, thus transmitting sound directly to the eardrum.