Mix-automatic sequences form a proper extension of the class of automatic sequences, and arise from a generalization of finite state automata where the input alphabet is state-dependent. In this paper we compare the class of mix-automatic sequences with the class of morphic sequences. For every polynomial
we construct a mix-automatic sequence whose subword complexity exceeds
. This stands in contrast to automatic and morphic sequences which are known to have at most quadratic subword complexity. We then adapt the notion of
-kernels to obtain a characterization of mix-automatic sequences, and employ this notion to construct morphic sequences that are not mix-automatic.