Dancing Money Vocoder!
Illustrates the technique of spectral cross-synthesis based on convolution of two signals. The signals can be of any origin.
In this case, a sequence of financial data is convolved with a dance track. The financial data (stored in the ascii wavetable
file "finance.txt") corresponds to the percentage daily price variation of oats (on the US commodities market) from March
1979 to November 1995.
The financial data is convolved with a dance track ("dance.wav"), thus imposing the underlying spectral characteristics
of the dance music on to the price fluctuations..
Try varying the parameters of all components to investigate the behaviour of the vocoder. Experiment with different audio
signals and driving signals (e.g. other financial time series !)
The Convolution block performs pure convolution of the two inputs. Although it uses the Fast Fourier Transform (FFT) for
efficiency, appropriate zero-padding and overlapping is applied to eliminate "circular convolution", such that the output is
exactly the direct convolution of the two inputs, as if the computations were carried out in the time domain. The only tell-tale
sign that the FFT has been used is the inherent "latency". In other words, the output is delayed by the length of the input
data buffer.
