A recent study compared the performance of Shure sound isolating earphones against three models of noise-canceling headphones and found that the sound isolating design was more effective at reducing the level of a broadband noise signal. The tests were conducted in accordance with recognized industry standards for measuring the noise attenuation capabilities of hearing protection devices and noise-canceling headphones.
The study results revealed that the E3c with foam sleeves was the best performer among the Shure units tested, as it reduced noise by 10 - 27 decibels more than even the best-performing noise-canceling model tested. Further, the data indicated that all of the Shure model variations tested provided greater overall noise reduction at the lower frequencies where noise-canceling models are reputed to be most effective.
Shure analyzed the test data and concluded that the difference in performance between sound isolating earphones and noise-canceling headphones is even greater than previously thought. "We found that the sound isolating earphones provided greater overall noise reduction than the noise-canceling models tested," explained Chris Lyons, manager, portfolio planning, Shure Personal Audio. "When we converted the study's decibel performance numbers into percentage figures, it became abundantly clear to us just how significant the performance differences are. The E3c earphones with foam sleeves reduced overall noise by 93%, far surpassing even the best-performing noise-canceling model in the test, which reduced noise by only 77%."
Products tested for the purpose of this study included the Shure E3c sound isolating earphones with foam and flex sleeves, Shure E2c sound isolating earphones with foam and flex sleeves, and the following noise-canceling models: Bose Quiet Comfort 2, Sennheiser PXC-250 and Sony MDR-NC20.
The products were tested for their ability to reduce the noise in standardized, one-third octave test bands over a six octave range. The decibel (dB) attenuation data were obtained in an independent testing facility, the Auditory Systems Laboratory at Virginia Tech, which is under the direction of Dr. John Casali, Grado Professor.
Shure performed interpretation of the results. The study utilized 10 subjects certified to have normal hearing, each of whom wore several noise-reducing headphones. To ensure accuracy, each subject was tested with each product on three separate occasions, utilizing procedures standardized by the American National Standards Institute.
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