The definition of a Timbre Space with the MIDL consists on the definition of three different aspects.
First, the number of dimensions to be used. The Instrument designer must decide what features of the Instrument represent a substantial change in the sound that cannot be achieved using the different transformations available. These dimensions such as loudness, pitch, articulation, etc... must have the corresponding SMS data extracted from a previous analysis of those features in the Instrument. A compromise between sound quality and amount of synthesizer memory used must be adopted.
Next, the kind of Interpolation to use between the Data stored. A set of standard interpolation types are available.
Finally, the positioning of each sample in a concrete location in the space must be given. The Instrument Class will be capable of solving intermediate positions by the interpolation of the SMS data loaded from the files.
E.g. A good quality piano sound can be obtained by storing the SMS Data from just eight of the piano keys (A0 thru A7) and obtaining the rest by interpolation. Thus, only one dimension is used (pitch). Other features such as loudness can be obtained by applying different transformations on the data available [Solà, 1997].