A headphone system comprising: a headband; and an earpiece mounted to the headband, the earpiece comprising: a can (20, 22) secured to the headband, the can (20, 22) comprising: a speaker (34, 35), a microphone that captures ambient environmental sound surrounding the environment, an amplifier circuit that amplifies a signal from the microphone including the captured ambient environmental sound, thereby providing an amplified ambient environmental sound, and a can body, the can body comprising a circumferentially-extending side wall surrounding the speaker (34, 35), and a circumferentially-extending open region defined between the speaker (34, 35) and the side wall, and circuitry that ceases the amplification of the ambient environmental sound by the amplifier circuit in response to an impulse sound exceeding an adjustable threshold, thereby enabling the headphone system to selectively capture and amplify environmental sounds from the ambient environment while blocking impulse sounds potentially damaging to a wearer's hearing; and an ear cup mounted to the can to overlie the speaker, wherein the ear cup comprises a sound absorbing element within the circumferentially-extending open region and comprises a sound absorbing layer overlying the sound absorbing element and the speaker. a headband; and an earpiece mounted to the headband, the earpiece comprising: a can (20, 22) secured to the headband, the can (20, 22) comprising: a speaker (34, 35), a microphone that captures ambient environmental sound surrounding the environment, an amplifier circuit that amplifies a signal from the microphone including the captured ambient environmental sound, thereby providing an amplified ambient environmental sound, and a can body, the can body comprising a circumferentially-extending side wall surrounding the speaker (34, 35), and a circumferentially-extending open region defined between the speaker (34, 35) and the side wall, and circuitry that ceases the amplification of the ambient environmental sound by the amplifier circuit in response to an impulse sound exceeding an adjustable threshold, thereby enabling the headphone system to selectively capture and amplify environmental sounds from the ambient environment while blocking impulse sounds potentially damaging to a wearer's hearing; and an ear cup mounted to the can to overlie the speaker, wherein the ear cup comprises a sound absorbing element within the circumferentially-extending open region and comprises a sound absorbing layer overlying the sound absorbing element and the speaker. a can (20, 22) secured to the headband, the can (20, 22) comprising: a speaker (34, 35), a microphone that captures ambient environmental sound surrounding the environment, an amplifier circuit that amplifies a signal from the microphone including the captured ambient environmental sound, thereby providing an amplified ambient environmental sound, and a can body, the can body comprising a circumferentially-extending side wall surrounding the speaker (34, 35), and a circumferentially-extending open region defined between the speaker (34, 35) and the side wall, and a speaker (34, 35), a microphone that captures ambient environmental sound surrounding the environment, an amplifier circuit that amplifies a signal from the microphone including the captured ambient environmental sound, thereby providing an amplified ambient environmental sound, and a can body, the can body comprising a circumferentially-extending side wall surrounding the speaker (34, 35), and a circumferentially-extending open region defined between the speaker (34, 35) and the side wall, and circuitry that ceases the amplification of the ambient environmental sound by the amplifier circuit in response to an impulse sound exceeding an adjustable threshold, thereby enabling the headphone system to selectively capture and amplify environmental sounds from the ambient environment while blocking impulse sounds potentially damaging to a wearer's hearing; and an ear cup mounted to the can to overlie the speaker, wherein the ear cup comprises a sound absorbing element within the circumferentially-extending open region and comprises a sound absorbing layer overlying the sound absorbing element and the speaker.