Denon's AHD1000 on-th-ear headphones are distinguished by two signature sound-enhancing technologies. First is the latest Micro-fiber Diaphragm technology. The smaller size of the micro-fiber (1/100th compared to natural cellulose) results in a denser diaphragmatic material which increases transmission rates for better sound and detail, affording maximum presence of acoustic sounds with low distortion. In addition, a special Acoustic Optimizer (in all five models) adjusts sound pressure balance in front and behind diaphragm to deliver dynamic bass sounds. The AH-D1000, available in either black or silver, provides a more portable high-quality sound that can be easily enjoyed outdoors as well as indoors.