There is a major difference between types of headphone technology being mentioned in this thread. There is the Bose and Sony headphone that utilize "noise cancellation" and the Peltor, Sordin, ProEars, WorkTunes etc. That DO NOT use "noise cancellation".
Noise Cancellation - these units are used for sound isolation. The electronics sample the ambient sound, reproduce it 180 degrees out of phase and re-introduce it into the earcup causing the sound waves to cancel. The Bose are not designed to let you hear your surroundings, only to block outside noise.
Electronic Ear Muffs (Peltor, Sordin, ProEars, WorkTunes etc) - are designed to let you hear outside sounds while wearing hearing protection. The ear muff is the hearing protection, The electronic amplifier lets you hear "through the earmuff" and then the amplifier is set to not over amplify loud sounds. Typically the amplifier limits its output to about 90-94 decibels. These type of products ARE NOT "noise cancellation" technology.
Adding the ability to listen to music, cell phones, etc. is secondary to the hearing protection provided by either type of headsets.
Noise Cancellation - these units are used for sound isolation. The electronics sample the ambient sound, reproduce it 180 degrees out of phase and re-introduce it into the earcup causing the sound waves to cancel. The Bose are not designed to let you hear your surroundings, only to block outside noise.
Electronic Ear Muffs (Peltor, Sordin, ProEars, WorkTunes etc) - are designed to let you hear outside sounds while wearing hearing protection. The ear muff is the hearing protection, The electronic amplifier lets you hear "through the earmuff" and then the amplifier is set to not over amplify loud sounds. Typically the amplifier limits its output to about 90-94 decibels. These type of products ARE NOT "noise cancellation" technology.
Adding the ability to listen to music, cell phones, etc. is secondary to the hearing protection provided by either type of headsets.