Last June, we tried on a pair of headphones like nothing wed tried before — headphones that used artificial muscles to make it feel like youre practically in the same room as your favorite musical artists. At the time, those headphones were just prototypes, but theyre about to become a reality. Mad Catz and Able Planet are about to ship the first set of headphones with the tech — starting this month with the $129.99 Mad Catz Freq4D. The Mad Catz product adapts the companys existing $99.99 Freq3 headphones to the ViviTouch electroactive polymer tech, effectively adding a miniature subwoofer behind the 50mm stereo speaker drivers that lets you feel low-frequency effects in games and music through the skin and bone around your ears.