ReSound provides illustration of all 6 mics (or 5) (or 4) working together.
OK. This is from Feature Demonstration in Smart Fit v1.8, under M&RIE. It shows how the activity of all 6 microphones varies with sound in the environment relative to speech and relative to where the user’s head is positioned. Because of copyright, I cannot post the 40 sec video animation but have screen-captured (fair use, I hope!) the different situations.
Quiet conversation. All 6 mics active.
Noise on left (other speech not in direction user facing), all 3 mics active for omnidirectional noise cancellation
Quieter Right Ear, M&RIE mic off, BTE mics beam focusing on speaker
Noise moves to right (other speech not in user-facing direction), mic focus shifts
All 3 right mics including M&RIE now on, 2 left BTE mics beam focused, left M&RIE off
Severe noise behind user (noisy vacuum cleaner)
Both M&RIE mics off, both set of BTE mics beam focused forward on speaker
The diagrams also relate to the info in this post and the Audiology Online course referenced: GN Hearing introduces ReSound ONE - #121 by jim_lewis