Parametric Resynthesis by Interpolated Signal models. Vaguely resembles certain aspects of Wavetable and physical-modeling synthesis, but it’s actually something new. This process starts with the recording of one or more notes. These recordings are then separated into pitched and un-pitched (noise) components, each of which is analyzed to determine its power envelope and spectral characteristics. A pitch envelope is also derived from the pitched component. The spectral characteristics are represented by a series of filter coefficients, which can vary in time along with the pitch and power envelopes. Once the analysis is complete, the derived parameters are used as a model to reconstruct the original sound and manipulate it in any number of ways. This is unlike physical modeling, which is based on complex equations that describe the general acoustic behavior of certain types of instruments. PRISM is based on specific recordings. This technique is called Signal Modeling.
Characteristics: 1. PRISM sounds are not looped. The derived parameters allow a note to be held for any duration, regardless of the original recording’s length. 2. Sustained notes are not static. All the irregularities of the original human player can be modeled and applied to the synthesized sound. 3. PRISM instruments can also include the natural vibrato, tremolo, and release of the original sound, and the formants do not shift along with the pitches of the notes. This system can smoothly interpolate between different sets of parameters, allowing seamless morphing between the timbral characteristics of notes played at soft and loud volumes, and low and high pitches, and even by completely different instruments. These activities can be placed under MIDI control.