### Objective:

It is known in psychoacoustics that not all information contained in a "real world" acoustic signal is processed by the human auditory system. More precisely, it turns out that some time-frequency components mask (overshadow) other components that are close in time or frequency.

In the software S_TOOLS-ST^{x} developed by the Institute, an algorithm based on simultaneous masking has been implemented. This algorithm removes perceptually irrelevant time-frequency components. In this implementation, the model is described as a Gabor multiplier with an adaptive symbol.

In this project, the masking model will be extended to a true time-frequency model, incorporating frequency and temporal masking.

### Method:

Experiments have been conducted (in cooperation with the Laboratory for Mechanics and Acoustics / CNRS Marseille) to test the time-frequency masking properties of a single Gaussian atom, and to study the additivity of these masking properties for several Gaussian atoms.

The results of these experiments will be used, in combination with theoretical results obtained in the parallel projects studying the mathematical properties of frame multipliers, to approximate or identify the masking model by wavelet and Gabor multipliers.

The obtained model will then be validated by appropriate psychoacoustical experiments.

### Application:

Efficient implementation of a masking filter offers many applications:

- Sound / Data Compression
- Sound Design
- Back-and-Foreground Separation
- Optimization of Speech and Music Perception

After completing the testing phase, the algorithms are to be implemented in S_TOOLS-STx.

### Publications:

- P. Balazs, B. Laback, G. Eckel, W. Deutsch, "Introducing Time-Frequency Sparsity by Removing Perceptually Irrelevant Components Using a Simple Model of Simultaneous Masking", IEEE Transactions on Audio, Speech and Language Processing (2009), in press
- B. Laback, P. Balazs, G. Toupin, T. Necciari, S. Savel, S. Meunier, S. Ystad and R. Kronland-Martinet, "Additivity of auditory masking using Gaussian-shaped tones", Acoustics'08, Paris, 29.06.-04.07.2008 (03.07.2008)
- B. Laback, P. Balazs, T. Necciari, S. Savel, S. Ystad, S. Meunier and R. Kronland-Martinet, "Additivity of auditory masking for Gaussian-shaped tone pulses", preprint