Can I use in-ear headphones with Reference 4? Viesturs Updated March 25, 2020 13:26 Follow No, in-ear headphones are not supported at the moment. Related articles Individual Headphone Calibration I received my individually calibrated headphones but there is no individual calibration file. Where do I get it? (Reference 4.2 & legacy versions) Where do I ship my headphones for individual calibration? How long does it take to calibrate my headphones? Setting up Individual Headphone Calibration Comments 0 comments Please sign in to leave a comment.