This project began as a prototype & then manufacturing service for Yuni (http://www.yuniheadphones.com/), which is attempting to build a set of stereo headphones for people with unilateral hearing loss. The Yuni has two distinct ear cups; one with two speakers in them angled at the ear to preserve separation of L/R channels, and one dummy cup with nothing in it. This version, called the Duli, is this original project adapted for un-impaired dual-hearing use (standard headphones).