Sony Japan has recently introduced wireless headphones that operate on the 2.4GHz frequency and, more importantly, can reproduce 7.1-channel audio. The MDR-DS7100 set has support for Dolby Digital, Dolby Digital EX, DTS and DTS-ES surround sound formats. Their range is said to be a long 98 feet, while battery life is also longer than for most simpler wireless headphones at 13 hours. Each earpiece packs a near 2-inch (50mm) driver.
