@article {Chung:February 2009:0018-7208:78,
	author = "Chung, King",
	author = "Tufts, Jennifer",
	author = "Nelson, Lance",
	title = "Modulation-Based Digital Noise Reduction for Application to Hearing Protectors to Reduce Noise and Maintain Intelligibility",
	journal = "Human Factors: The Journal of the Human Factors and Ergonomics Society",
	volume = "51",
	year = "February 2009",
	abstract = "<B>Objective:</B> The objective of this study was to test the effects of modulation-based digital noise reduction (MB-DNR) on noise levels, speech intelligibility, and listening preference in four real-world noises. <B>Background:</B> A significant challenge in hearing protection device (HPD) design is to reduce ambient noise levels while maintaining users' ability to understand speech. MB-DNR technology, currently employed in hearing aids, potentially could be used to achieve these objectives. <B>Methods:</B> Speech and noise calibrated to signal-to-noise ratios (SNRs) of 0, &#8722;5, and &#8722;10 dB in the sound field were recorded at the outputs of two digital hearing aids in the ears of a Knowles Electronic Manikin for Acoustic Research with and without MB-DNR activated (i.e., NR and noNR, respectively). Listeners' speech intelligibility scores and sound quality preferences were evaluated while they listened to the recordings presented via ER-3A insert earphones at 85 dB SPL. <B>Results:</B> MB-DNR reduced the overall noise level by approximately 4 to 7 dB. Listeners obtained significantly higher speech intelligibility scores in the NR condition at an SNR of &#8722;10 dB in two noises and similar scores in the noNR and NR conditions in all other cases. They preferred the NR condition in all cases. <B>Conclusion:</B> MB-DNR reduced overall noise level, enhanced sound quality, and maintained or improved speech intelligibility in the four military noises tested. <B>Applications:</B> MB-DNR algorithms potentially could be incorporated into HPDs to enhance performance and increase user acceptance.",
	pages = "78-89(12)",
	url = "http://www.ingentaconnect.com/content/hfes/hf/2009/00000051/00000001/art00007"
	doi = "doi:10.1177/0018720809333083"
}