Reference Audio Systems - RAAL-Requisite World's first Earfield™ Monitor – True-Ribbon™ headphone The SR1a by RAAL-requisite is the world's first Earfield™ Monitor. Experience mixing, mastering, and home listening with unparalleled accuracy and
Bolt from the Blue: RAAL-requisite SR1a "EarField™ Monitors" - Headphone Review – Headphones.com