Sony MDR-EX90SL Earphones Fit a 13.5mm Driver into a 9mm Hole
Paying close attention laws of physics, Sony created a pair of earphone drivers that are large enough to give you big sound but have a smaller swiveling tip that’s 9mm in diameter, just able to fit into your ear canal. These 13.5mm drivers are able to inject 5-25,000Hz of audio goodness into your skull, according…