Ultra-pure drivetrain sound recording of a BYD Han EV in a vacuum-sealed anechoic chamber (air pressure < 0.01 Pa) with the vehicle suspended on active magnetic bearings (vibration isolation >50 dB at 10-1000 Hz). The drivetrain operates at 120 km/h equivalent motor speed (18,000 rpm), emphasizing the 2500 Hz fundamental harmonic (±3 Hz tolerance) and its 3rd overtone at 7500 Hz. Explicitly exclude all non-drivetrain noise: no tire contact, wind resistance, or structural vibrations.