Multiband compression hearing aids: developing a performance metric

When attempting to compare different compression algorithms used in multiband compression hearing aids, or different parameter settings of a given compression algorithm, there is a need to compare equivalent amounts of compression. Since there are several parameters that influence the actual amount of compression that occurs, it is desirable to know which set of parameters will create the least perceptual difference from the original signal for a given amount of compression. Unfortunately, there is not a well defined approach for determining the amount of compression that has been imparted to a signal. Two degree of compression metrics are proposed that can be used to determine the amount of compression by direct analysis of the audio signal before and after compression. These metrics give excellent results in predicting the ratings of subject-based testing on the audio quality of several different audio segments across several parameter variations.