Two concepts are presented, extended, and unified in this paper: mobile device augmentation towards musical instruments design and the concept of hybrid instruments. The first consists of using mobile devices at the heart of novel musical instruments. Smartphones and tablets are augmented with passive and active elements that can take part in the production of sound (e.g., resonators, exciter, etc.), add new affordances to the device, or change its global aesthetics and shape. Hybrid instruments combine physical/acoustical and "physically informed" virtual/digital elements. Recent progress in physical modeling of musical instruments and digital fabrication is exploited to treat instrument parts in a multidimensional way, allowing any physical element to be substituted with a virtual one and vice versa (as long as it is physically possible). A wide range of tools to design mobile hybrid instruments is introduced and evaluated. Aesthetic and design considerations when making such instruments are also presented through a series of examples.

Virtual Reality (VR) and digital fabrication technologies today are ushering in a new wave of opportunities in instrument design; the marriage of these two domains, seemingly at odds with each other, can bring impossible instruments to life. In this article, the authors first sample such instruments throughout history. The authors also look at how technology has facilitated the materialization of impossible instruments from the twentieth century on. They then discuss the bridging of VR and fabrication as a new frontier in instrument design, where synthetic sounds can be used to condition an equally synthetic sensory scaffolding upon which the time-varying spectra can be interactively anchored: The result is new instruments that can defy our sense of audiovisual reality while satisfying our proprioceptive and haptic expectations. The authors report on their ongoing work as well as their projections of how emerging technologies in VR and fabrication will shape the design of new musical interfaces.

Accurately predicting acoustical properties of 3D printed models is of interest to instrument designers who explore novel geometries. We introduce a technique to carry out these estimates using a database of impulse responses and mode interpolation. 3D models are organized as a function of their physical characteristics and placed into a multidimensional space/matrix. The models at the boundaries of this space define the limits of our prediction algorithm and they are produced using 3D printing. Impulse responses of these models are measured, and modal information is extracted from each object. Mode parameters are interpolated within the matrix to predict the frequency response of unprinted models that fall within the geometrical space of the test matrix. A physical model using modal synthesis also allows us to listen to the resulting resonator.

Music rehearsal and concert performance at a distance over long-haul optical fiber is a reality because of expanding network capacity to support low-latency, uncompressed audio streaming. Multichannel sound exchanged across the globe in real time creates “rooms” for synchronous performance. Nearby connections work well and musicians feel like they are playing together in the same room. Larger, continental-size, distances remain a challenge because of transmission delay and seemingly subtle but perceptually important cues which are in conflict with qualities expected of natural rooms. Establishing plausible, room-like reverberation between the endpoints helps mitigate these difficulties and expand the distance across which remotely located musicians perform together comfortably. The paper presents a working implementation for distributed reverberation and qualitative evaluations of reverberated versus non-reverberated conditions over the same long-haul connection.