Overview The DT 990 Pro X  builds on the long-standing Beyerdynamic legacy of reference-grade open-back headphones, redesigned with the modern audio creator in mind. It uses the newer STELLAR.45 driver  system with a wide 5 Hz–40 kHz frequency range and 48 Ω impedance , making it easier to drive from a range of sources — from audio interfaces and laptops to mobile devices — without the need for heavy amplification. Sound Quality Detailed and Accurate Treble & Detail:  These h