In Western music, tuning systems have continuously changed over time. Each system is, in a certain way, tied to specific compositional, instrumental and acoustic demands. Tuning systems do not emerge immediately and with a clear purpose; they come inspired and colored with stylistic qualities, instrumental construction requirements, influence of aesthetics from the past, or even the renewal of philosophical conceptions and consequent rupture with previous practices. As a result, it generally changes the entire musical panorama and practices as well as the instruments used.

Moreover, the 20th and 21st centuries saw a rise of new interpretative possibilities and challenges due to innovations brought by different composers and compositional schools in the percussion repertory. Harry Partch, John Cage, James Wood, Iannis Xenakis, Bryan Ferneyhough, Volker Staub and Walter Smetak are some examples of those who, in search for new sound possibilities and specific timbres, increased the development of new percussion instruments.

Most of the research on tuning systems and tuning models in music does not focus on performance issues. In this regard, much information remains uncollected or simply lacking of a pertinent discussion. A discussion connecting percussion instruments, musical performance and tuning phenomena would be an important contribution to the research in the field.

In the light of this context, the present research intends to discuss three fundamental points: which resources are offered for the performance of specific tuning systems; which resources for musical expression have certain aesthetical currents sought in the tuning material they have adopted; and how does the construction of new instruments arise new performance questions, and, more specifically, new perspectives on tuning metal percussion keyboards.

It is why this research has three main purposes: relating, describing and discussing tuning systems and tuning models for metal percussion, discussing the performance of works requiring specific tuning models in metal percussion instruments, observing how different tuning systems are used by some contemporary musicians and composers.

The project will focus initially on works by Lou Harrison (and his references to Eastern gamelan) and Iannis Xenakis (who for example created a new instrument, the Sixxen, influenced by works and ideas of ancient Greece).