Golden Ears Test System - for more information (Link) 1. HATS: Bruel & Kjær - Head and Torso Simulator Type 4128C 2. Microphone Amplifier: Bruel & Kjær - NEXUS Conditioning Amplifier 3. Audio Interface: Lynx L22 4. DAC: Golden Ears D/A Converter 5. Headphone Amplifier: Golden Ears Headphone Amplifier