I'm finding many different ways to combine these two tracks. This time I'm convolving the two tracks - basically the spectral information from one track controls the frequency information of the other, or as Wikipedia puts it, "In mathematics and in particular, functional analysis, convolution is a mathematical operator which takes two functions f and g and produces a third function that in a sense represents the amount of overlap between f and a reversed and translated version of g. A convolution is a kind of very general moving average, as one can see by taking one of the functions to be an indicator function of an interval."
This is the same technique that is used to apply the sampled acoustics of a space to a sound source, which, as you know, I do quite a bit. 2005-10-07
An audio-specific explanation of convolution can be found at Barry Truax's webpage.