3D Audio

Our research activity concerns the development of innovative techniques for spatial audio synthesis with particular attention to binaural audio synthesis and real-time audio rendering. We analyze the contribution of the external ear (pinna, PRTF) in relation to personal HRTF, proper to each individual, and model the physical features that have a perceptual interest for vertical localization of sound. The two main objectives are:

Customized HRTF models

The long-term goal is the implementation of structural models of head-related transfer functions (HRTFs) for binaural synthesis that approximate the real behaviour of the auditory space, to be applied in a real-time context to any subject.

Pinna images

We have designed an algorithm for the decomposition of pinna-related transfer functions (PRTFs) into ear resonances and frequency notches due to reflections over pinna cavities and following that we set up a method for extracting the frequencies of the most important spectral notches. Ray-tracing on different pinna images reveals a convincing correspondence between extracted frequencies and pinna cavities. The proposed model for PRTF synthesis allows to control the behaviour of resonances and spectral notches separately through the design of two distinct filter blocks, and is suitable for integration into a structural HRTF model and for parametrization over anthropometrical measurements.

Mixed structural modeling

We propose a novel framework for synthetic HRTF design and customization, that combines the structural modeling paradigm with other HRTF selection techniques: namely, the Mixed Structural Modeling (MSM) approach regards the global HRTF as a combination of structural components, which can be chosen to be either synthetic or recorded components. In both cases, customization is based on individual anthropometric data, which are used to either fit the model parameters or to select a recorded component within a set of available responses.


The research process aims at building a completely customizable structural model through subsequent refinements, starting from a selection of recorded HRIRs to a totally synthetic filter model. The intermediate steps are balanced mixtures of selected pHRIRs and synthetic structural components.

Application areas

A bunch of example application areas of 3D audio technologies are:

KEMAR with headphones

Research Threads

3D Audio
Audio in multimodal interfaces
Audio restoration
Interactive environments for learning
Music expression modeling
Physically-based sound modeling
Virtual rehabilitation

History of CSC research


Customized HRTF models
Mixed structural modeling
Application areas


A complete list of projects and industrial partners can be found here.