Frequency, Amplitude, Spectrum, and Ambience. An audio production method which is based on the criteria that can be changed in sonic terms to enhance a recording:
Frequency: Pitch, transposing parts, chord inversions, layering with other octaves.
Amplitude: Level, use of dynamic range to cut and boost sections, and relative volumes among parts.
Spectrum: Textures and the range of frequencies present, layering sounds with others, introducing new textures from other parts, changing the sounds for a part, like playing a percussion line as a bass part, the contrast in frequency and textures used.
Ambience: Space, reverb, and image information such as panning, depth, height, forward or recessed, for each part playing.