Studio reference class, open back, dynamic headphones with flat frequency response made in the EU. Hand picked and left / right matched transducers delivering accuracy and instrument separation. (+/-1 more→dB SPL tolerance, pink noise, range 100Hz-10kHz in free field). 50 mm, PET 25u membrane, 2 layered coil, 32 ohms. Dynamic Neodymium speaker with 109dBSPL (S4X) / 111dBSPL (S4R) 1Vrms@1KHz 30ohm output that makes them work with smart devices too. Replaceable earpads with outer diameter of 90 mm(3.5inch), inner diameter of 55mm(2.2inch) and depth of 20mm(0.8inch). Hybrid artificial leather and velour earpads to control flow resistance around the earpads seal resulting in smoother response in low mids …