High Performance External USB DAC and Audio Amplifier The Sound Blaster X7 Limited Edition has never looked this classy, with a touch of elegance. This pearl white edition certainly takes to the next level with the ultimate audio upgrade for pro-gamers and audio enthusiasts. A room-pleaser with unparalleled sound quality, the Sound Blaster X7 reflects the skill of its exclusive 1 ohm headphone amp output impedance, with a nice kick of extra audio amplification power.