  Multi-channel Multi-tone Active Noise Equalizers can achieve different
user-selected noise spectrum profiles even at different space positions. They
can apply a different equalization factor at each noise frequency component and
each control point. Theoretically, the value of the transfer function at the
frequencies where the noise signal has energy is determined by the equalizer
configuration. In this work, we show how to calculate these transfer functions
with a double aim: to verify that at the frequencies of interest the values
imposed by the equalizer settings are obtained, and to characterize the
behavior of these transfer functions in the rest of the spectrum, as well as to
get clues to predict the convergence behaviour of the algorithm. The
information provided thanks to these transfer functions serves as a practical
alternative to the cumbersome statistical analysis of convergence, whose
results are often of no practical use.
