#### Linear Prediction Order Selection

For computing spectral envelopes via linear prediction, the order
of the predictor should be chosen large enough that the envelope can
follow the contour of the spectrum, but not so large that it follows
the spectral ``fine structure'' on a scale not considered to belong in
the envelope. In particular, for voice,
should be twice the
number of spectral *formants*, and perhaps a little larger to
allow more detailed modeling of spectral shape away from the formants.
For a sum of quasi sinusoids, the order
should be significantly
less than twice the number of sinusoids to inhibit modeling the
sinusoids as spectral-envelope peaks. For filtered-white-noise,
should be close to the order of the filter applied to the white noise,
and so on.

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Summary of LP Spectral Envelopes

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Computation of Linear Prediction Coefficients