With the new Astra majoring on refinement, Vauxhall has revealed the process that went into keeping the cabin noise levels to a minimum.
The Astra was taken to Vauxhall/Opel's acoustic lab, whilst it was still in the final phase of being made production-ready. Engineers, led by Bernd Justen, Vehicle Performance Manager for Vauxhall/Opel's compact car class, are responsible for ensuring that these vehicles meet the noise requirements, and tested the Astra thoroughly in the company's acoustic lab in Russelsheim.
Vauxhall then put the Astra through its paces in the comfort and noise evaluation track at the Dudenhofen Test Centre in Germany, where all new Vauxhall/Opel models come for final testing.
Reducing NVH (noise, vibration, harshness) in the new Astra's cabin was of high priority, especially from the turbo-charged petrol and diesel engines that power it.
Justen continues: "That is only one aspect we check in the acoustic lab. Apart from the appropriate sound of the engine or rolling noise, this includes the sound made by closing a door or the clicking of the indicator. We initially check the simulation-based basic settings. Based on this we keep on working until the Astra meets our noise requirements."
The walls and the ceiling of the lab are completely soundproof thanks to noise absorbing materials. During testing, the Astra is driven on large floor rollers, which produce the same resistance the car would experience on the road from wind and rolling resistance.
Vauxhall also places 'dummy heads' in the cabin. As Justen explains: "There are highly sensitive microphones fitted in the ears of dummy heads too. They allow us to record and replay noises in the same way that a 'real' human would perceive them."
by: Oliver Harry