A method includes receiving a first value of a mixing factor. The first value corresponds to a first portion of an audio signal received at an audio encoder. The method includes receiving a second value of the mixing factor. The second value corresponds to a second portion of the audio signal. The method also includes generating a third value of the mixing factor at least partially based on the first value and the second value and mixing an excitation signal with modulated noise based on the third value. Another method includes determining a first set of spectral frequency values corresponding to an audio signal and determining a second set of spectral frequency values that approximates the first set of spectral frequency values. A gain value corresponding to at least a portion of the audio signal is adjusted based on a difference between the first set and the second set.