Shure: E3c Better Noise Blockers
But of the many models on the market, which are the best? A research project sponsored by Shure, Inc. found that the company's own E3c earphones were most effective at blocking outside noise. Employing industry standard techniques for evaluating hearing protection devices, the study compared three popular models of noise-canceling headphones against Shure's noise-blocking design and found that the sound-isolating design was more effective at reducing the level of a broadband noise signal, and was especially effective in the lower frequencies.
The E3c with foam sleeves reduced noise "by 10–27dB more than even the best-performing noise-canceling model tested," according to the report. "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," said Shure Personal Audio manager Chris Lyons. "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%." A further advantage to the noise-blocking design is that unlike some bulky noise-canceling phones, the lightweight E3c does not require batteries.
The study compared the Shure E3c sound-isolating earphones with foam and flex sleeves, the Shure E2c sound-isolating earphones with foam and flex sleeves, the Bose Quiet Comfort 2, the Sennheiser PXC-250, and the Sony MDR-NC20. All five "were tested for their ability to reduce noise in standardized, one-third octave test bands over a six-octave range," using ten subjects previously tested to establish their normal hearing. Test data from three separate sessions were obtained by the Auditory Systems Laboratory at Virginia Tech, an independent testing facility under the direction of Dr. John Casali. Shure, Inc interpreted the study's results.
Shure E3c earphones were reviewed by John Atkinson in May 2004, who points out that noise-reduction abilities of the 'phones, as well as the bass performance depend on the fit of the foam or soft plastic ear-plugs (Shure can supply several different sizes).