Consider some audio file, e.g.,
file = Audio[File["ExampleData/car.mp3"]]
Is it possible to represent its signal in a form
$f(t) = \sum_{n = n_{\text{min}}}^{n_{\text{max}}}a_{n}e^{int}$,
where $t$ denotes time, using Mathematica? I.e., to calculate the amplitudes $a_{n}$