Asus Xonar Phoebus ROG control box headphone output: 10 Ω
Asus Xonar Phoebus ROG front speaker output: 94 Ω
Sound Blaster X-Fi Titanium: 32 Ω
Sound Blaster X-Fi HD USB: 32 Ω
Sound Blaster X-Fi Surround 5.1 Pro USB: 10.0 Ω
Sound Blaster Recon3D USB: 0.8 Ω
Sound Blaster Tactic3D Sigma USB: 0.8 Ω
Audioengine D1 USB: 9.5 Ω
Asus Maximus Formula VI speaker out (Realtek ALC1150): 94 Ω
Asus Maximus Formula VI headphone out (Realtek ALC1150): 37 Ω