Reference montage is referring to your references on the ears. There is a choice between Linked and Unlinked. We primarily use Linked ears because it provides the most consistent data across the scalp. The two different types on montages that we use are mono and bipolar.  A mono polar montage with have the ears linked in the software and a bipolar montage with have the ears unlinked in the software.  Below is an example of a mono and bipolar montage. A monopolar montage is normally used to increase or decrease the magnitude of specific frequency bands.  A bipolar montage is used to increase or decrease the coherence of a specific frequency band.