Predicting the Perceptual Acceptability of Auditory Interference for the Optimisation of Sound Zones.

This work is part of the Perceptually Optimised Sound Zone project (posz.org) which aims to develop sound zoning systems which reproduce audio programmes to multiple listening zones within automotive and domestic environments. This work describes the construction of a model to evaluate sound zoning systems. A framework for evaluating auditory interference scenarios is described in which either the target or interferer programme is masked, or where both programmes are audible and the listening scenario has some degree of acceptability. Masking and acceptability experiments were conducted to investigate the relationship between the two, and to determine boundaries of audibility. A linear correlation was found between masking and acceptability, and a linear regression model was constructed to predict thresholds of acceptability from masking thresholds. A masking threshold model was adapted and predictions were within 3 dB of the reported mean masking thresholds. Predictions of acceptability, using a linear regression and masking model combination, accounted for three quarters of the variance in acceptability. Further work focused on speech target programmes based on listener comments that the presence of speech affected acceptability. An experiment was conducted to gather intelligibility and acceptability data. Results showed that a high speech intelligibility marked the lower boundary of acceptability. Existing models for intelligibility prediction were evaluated and a time-windowed speech intelligibility index was shown to predict intelligibility with RMSE = 10.8%. Subsequently, a model was constructed to predict acceptability within these boundaries. Two experiments were conducted gathering training and validation data, and a training and selection procedure was carried out to methodically identify the most useful features. The selected model predictions had acceptability scores of RMSE = 11.1-17.9% across training and validation data. Finally, an algorithm was proposed for the prediction of acceptability in auditory interference scenarios. The algorithm consists of first predicting masking thresholds to determine the boundaries of acceptability. Then, for non-speech target programmes, the acceptability is predicted using a linear regression to the masking threshold; for speech target programmes, the intelligibility is calculated to revise the lower acceptability boundary and the speech acceptability model is used to predict acceptability

Predicting the Perceptual Acceptability of Auditory Interference for the Optimisation of Sound Zones.

This work is part of the Perceptually Optimised Sound Zone project (posz.org) which aims to develop sound zoning systems which reproduce audio programmes to multiple listening zones within automotive and domestic environments. This work describes the construction of a model to evaluate sound zoning systems. A framework for evaluating auditory interference scenarios is described in which either the target or interferer programme is masked, or where both programmes are audible and the listening scenario has some degree of acceptability. Masking and acceptability experiments were conducted to investigate the relationship between the two, and to determine boundaries of audibility. A linear correlation was found between masking and acceptability, and a linear regression model was constructed to predict thresholds of acceptability from masking thresholds. A masking threshold model was adapted and predictions were within 3 dB of the reported mean masking thresholds. Predictions of acceptability, using a linear regression and masking model combination, accounted for three quarters of the variance in acceptability. Further work focused on speech target programmes based on listener comments that the presence of speech affected acceptability. An experiment was conducted to gather intelligibility and acceptability data. Results showed that a high speech intelligibility marked the lower boundary of acceptability. Existing models for intelligibility prediction were evaluated and a time-windowed speech intelligibility index was shown to predict intelligibility with RMSE = 10.8%. Subsequently, a model was constructed to predict acceptability within these boundaries. Two experiments were conducted gathering training and validation data, and a training and selection procedure was carried out to methodically identify the most useful features. The selected model predictions had acceptability scores of RMSE = 11.1-17.9% across training and validation data. Finally, an algorithm was proposed for the prediction of acceptability in auditory interference scenarios. The algorithm consists of first predicting masking thresholds to determine the boundaries of acceptability. Then, for non-speech target programmes, the acceptability is predicted using a linear regression to the masking threshold; for speech target programmes, the intelligibility is calculated to revise the lower acceptability boundary and the speech acceptability model is used to predict acceptability

Selection of temporal windows for the computational prediction of masking thresholds

In the field of auditory masking threshold predictions an op- timal method for buffering a continuous, ecologically valid programme combination into discrete temporal windows has yet to be determined. An investigation was carried out into the use of a variety of temporal window durations, shapes, and steps, in order to discern the resultant effect upon the accu- racy of various masking threshold prediction models. Selec- tion of inappropriate temporal windows can triple the predic- tion error in some cases. Overlapping windows were found to produce the lowest errors provided that the predictions were smoothed appropriately. The optimal window shape varied across the tested models. The most accurate variant of each model resulted in root mean squared errors of 2.3, 3.4, and 4.2 dB

THE COMPUTATIONAL PREDICTION OF MASKING THRESHOLDS FOR ECOLOGICALLY VALID INTERFERENCE SCENARIOS

Abstract Auditory interference scenarios, where a listener wishes to attend to some target audio while being presented with interfering audio, are prevalent in daily life. The goal of developing an accurate computational model which can predict masking thresholds for such scenarios is still incomplete. While some sophisticated, physiologically inspired, masking prediction models exist, they are rarely tested with ecologically valid programmes (such as music and speech). In order to test the accuracy of model predictions human listener data is required. To that end a masking threshold experiment was conducted for a variety of target and interferer programmes. The results were analysed alongside predictions made by the computational auditory signal processing and prediction model (CASP) described b

The Relationship Between Target Quality and Interference in Sound Zone

Sound zone systems aim to control sound fields in such a way that multiple listeners can enjoy different audio programs within the same room with minimal acoustic interference. Often, there is a trade-off between the acoustic contrast achieved between the zones and the fidelity of the reproduced audio program in the target zone. A listening test was conducted to obtain subjective measures of distraction, target quality, and overall quality of listening experience for ecologically valid programs within a sound zoning system. Sound zones were reproduced using acoustic contrast control, planarity control, and pressure matching applied to a circular loudspeaker array. The highest mean overall quality was a compromise between distraction and target quality. The results showed that the term “distraction” produced good agreement among listeners, and that listener ratings made using this term were a good measure of the perceived effect of the interferer

The relationship between target quality and interference in sound zones

Sound zone systems aim to produce regions within a room where listeners may consume separate audio programs with minimal acoustical interference. Often, there is a trade-off between the acoustic contrast achieved between the zones, and the fidelity of the reproduced audio program (the target quality). An open question is whether reducing contrast (i.e. allowing greater interference) can improve target quality. The planarity control sound zoning method can be used to improve spatial reproduction, though at the expense of decreased contrast. Hence, this can be used to investigate the relationship between target quality (which is affected by the spatial presentation) and distraction (which is related to the perceived effect of interference). An experiment was conducted investigating target quality and distraction, and examining their relationship with overall quality within sound zones. Sound zones were reproduced using acoustic contrast control, planarity control and pressure matching applied to a circular loudspeaker array. Overall quality was related to target quality and distraction, each having a similar magnitude of effect; however, the result was dependent upon program combination. The highest mean overall quality was a compromise between distraction and target quality, with energy arriving from up to 15 degrees either side of the target direction