Research Article The Acoustic and Peceptual Effects of Series and Parallel Processing | Hindawi Publishing Corporation EURASIP Journal on Advances in Signal Processing Volume 2009 Article ID 619805 20 pages doi 2009 619805 Research Article The Acoustic and Peceptual Effects of Series and Parallel Processing Melinda C. Anderson 1 Kathryn H. Arehart 1 and James M. Kates1 2 1 SLHS-Speech Department of Speech Language and Hearing Science University of Colorado at Boulder 409 UCB Boulder CO 80309 USA 2 GN Resound 2601 Patriot Blvd. Glenview IL 60026 USA Correspondence should be addressed to Melinda C. Anderson Received 8 December 2008 Revised 5 June 2009 Accepted 5 August 2009 Recommended by Torsten Dau Temporal envelope TE cues provide a great deal of speech information. This paper explores how spectral subtraction and dynamic-range compression gain modifications affect TE fluctuations for parallel and series configurations. In parallel processing algorithms compute gains based on the same input signal and the gains in dB are summed. In series processing output from the first algorithm forms the input to the second algorithm. Acoustic measurements show that the parallel arrangement produces more gain fluctuations introducing more changes to the TE than the series configurations. Intelligibility tests for normal-hearing NH and hearing-impaired HI listeners show 1 parallel processing gives significantly poorer speech understanding than an unprocessed UNP signal and the series arrangement and 2 series processing and UNP yield similar results. Speech quality tests show that UNP is preferred to both parallel and series arrangements although spectral subtraction is the most preferred. No significant differences exist in sound quality between the series and parallel arrangements or between the NH group and the HI group. These results indicate that gain modifications affect intelligibility and sound quality differently. Listeners appear to have a higher tolerance for gain modifications with regard to intelligibility while .
