The subjective test methodology described in this Recommendation1 provides means to evaluate the quality degradation introduced by the transmission over stereo telecommunication systems that provide users with a spatial experience.

The methodology conditions test subjects to attend to various aspects of the auditory signal presented over headphones, specifically, signal quality and spatial localization, in making their judgments of overall quality

The methodology is intended for use with naive subjects and headphone presentation and allows for evaluating at least 18 test conditions in a single test.

The methodology is well suited to evaluate the impact of a stereo coding stage on the spatial localization, signal quality and overall quality of signals. The methodology is not intended for the evaluation, or comparison, of spatial rendering techniques.

The evaluation has been carried out for clean speech signal