The TwinMic™ directional microphone system includes two independent microphones. This type of microphone is available in most Siemens hearing instrument families (e.g. CENTRA™, ACURIS™, ARTIS™, CIELO™, PRISMA2™ - to name but a few). TwinMic is a high-performance, well-designed directional microphone with excellent directivity (AI-DI = 4.2 dB) and with additional adaptive directional characteristics available in some instrument types. A special algorithm ensures that the directional characteristics of the microphone are adapted so that loud background noise is attenuated. If the noise source moves relative to the hearing instrument user, the directivity adapts to the movement. Adaptation is performed continuously and without noticeable transitions. ACURIS and ARTIS hearing instruments can attenuate up to four moving noise sources in different frequency bands. TRIANO and CIELO instruments are only able to attenuate the loudest moving noise source.

In addition to the ability to adaptively modify directivity and fade out moving background noise, the Siemens directional microphone system switches between the omnidirectional microphone and the directional microphone in the automatic program. Hearing instrument users no longer need to manually switch between microphones to adjust to variable hearing situations - their hearing instrument works for them.

The automatic directional microphone system only activates the directional microphone when it is really needed. In quiet situations when the surrounding noise level is below approx. 60 dB, the omnidirectional microphone is activated. The system fades over to the directional microphone at higher levels. This soft-fading technique prevents "hard switching" which is unpleasant and irritating for the hearing instrument user.