This portfolio of compositions investigates the adaptation of state-space models, frequently used in engineering control theory, to the electroacoustic composition context. These models are mathematical descriptions of physical systems that provide several variables representing the system's behaviours.The composer adapts a set of state-space models of either abstract, mechanical or electrical systems to a music creation environment. She uses them in eight compositions: five mixed media multi-channel pieces and three mixed media pieces.In the portfolio, the composer investigates multiple ways of meaningfully mapping these system's behaviours into music parameters. This is done either by exploring and creating timbre in synthetic sound, or by transforming existing sounds. The research also involves the process of incorporating state-space models as a real-time software tool using Max and SuperCollider.As real-time models offer several variables of continuous evolutions, the composer mapped them to different dimensions of sound simultaneously. The composer represented the model's evolutions with either short/interrupted, long or indefinitely evolving sounds. The evolution implies changes in timbre, length and dynamic range. The composer creates gestures, textures and spaces based on the model's behaviours.The composer explores how the model's nature influences the musical language and the integration of these with other music sources such as recordings or musical instruments. As the models represent physical processes, the composer observes that the resulting sounds evolve in organic ways. Moreover, the composer not only sonifies the real-time models, but actually excites them to cause changes. The composer develops a compositional methodology which involves interacting with the models while observing/designing changes in sound.In that sense, the composer regards real-time state-space models as her own instruments to create music. The models are regarded as additional forces and as sound transforming agents in mixed media pieces. In fixed media pieces, the composer additionally exploits their linearity to create space through sound de-correlation.