SALTO is a software based synthesizer. It is also based on the SMS technique (see Annex B). It implements a general architecture for these synthesizers but it is currently only prepared to produce high quality sax and trumpet synthesis. Pre-analyzed data are loaded upon initialization. The synthesizer responds to incoming MIDI data or to musical data stored in an XML file. Output sound can be either stored to disk or streamed to the sound card on real-time. Its GUI allows to modify synthesis parameters on real-time. Figure 3.10 reproduces a schematic representation of the application.
The synthesizer uses a database of SDIF files that contain the result of previous SMS analysis. These SDIF files contain spectral analysis samples for the steady part of some notes, the residual and the attack part of the notes. These SDIF files can be viewed, transformed and synthesized with the previously explained SMSTools.
Apart from this SDIF input, SALTO has three other possible inputs: MIDI, an XML Melody, and the GUI. Using MIDI as an input SALTO can be used as a regular MIDI synthesizer on real-time. SALTO is prepared to accept MIDI messages coming from a regular MIDI keyboard or a MIDI breath controller. On the other hand if an XML melody is used as an input this melody is synthesized back. It is the easiest way to try that SALTO is working correctly. Finally the GUI can be basically used to control the way the synthesis is going to work and to test configurations by generating single notes.
As seen in the screenshot in figure 3.11, the most important part of the interface is on the lower left: the buttons to select what part of the sound you would like to synthesize. The upper part of the interface is just a graphical display of the output. On the right there are two buttons for loading and playing an XML melody. Finally, the central part is designed to manage the database.