Vehicle Semi-Anechoic Chamber

At a glance

Millbrook’s semi-anechoic chamber in the UK enables vehicle and transmission NVH tests to be completed in a controlled, repeatable environment with low levels of background noise.

Vehicle NVH testing in a semi-anechoic chamber at Millbrook
Vehicle NVH testing in a semi-anechoic chamber at Millbrook

Twin rollers are connected to a 350kW DC machine dynamometer, enabling high power vehicles to be tested using a wide range of drive profiles. The room will accommodate vehicles up to the largest trucks and buses.

  • Entrance door size: 4.7m (high) x 3.8m (wide)
  • Working area: 19m x 9m x 5m
  • Background noise: 40dB (lin)
  • Lower cut-off frequency: 70Hz
  • Power absorption: 350kW (50 - 130km/h)
  • Drive back: 300kW (50 - 130km/h)
  • Tractive Effort: 36kN
  • Speed: 0 - 130km/h
  • Rollers: 1,200mm diameter, 1,350mm centres
  • Tyres: 700mm - 1,200mm diameter
  • Road load simulation: vehicle inertias to 40kN, simulation of gradients +/-40kN
  • Braking inertia: simulation up to 20T
  • Max braking force: 200kN (=1g at 20T)
  • Chamber ventilation: noise free extraction up to 3.5m/s aux fans for ram-air cooling
  • Vehicle benchmarking, characterisation and design validation
  • Investigation of noise and vibration performance (transmission path analysis, running mode analysis; NVH testing)
  • Powertrain noise investigations
  • Driveline and axle investigations
  • Exhaust system noise and vibration measurement
  • Disconnect exercises
  • Acoustic transfer function measurement
  • Exhaust system transmission loss/ insertion loss tests
  • Driveline durability testing
  • Driveline vibration investigations
  • Acoustic testing of individual components requiring very low background noise