The ERL value in the AEC block should be between 0 to +15 to work properly. One of the simplest tricks for adjusting this level is to place a level block before the AEC REF and adjust the level there. Placing a separate level block in front of the AEC reference, instead of adjusting the level via the Matrix, makes the adjustment more visible to anyone viewing the design.
To read more about AEC in Tesira, please visit this article:
AEC in Tesira - Biamp Cornerstone