A fully electric car gives automakers a bit more headaches in terms of noise insulation. With no combustion engine to cancel wind and tyre noises, you begin to hear more unwanted sounds. That's obviously not acceptable for a fullsize premium saloon, which is why BMW is going the extra mile to make the cabin of its next-generation 7 Series a veritable luxury cocoon.

The next episode in the i7's teaser campaign takes us to Munich at BMW's new Research and Innovation Centre (FIZ) where the sound emissions and immissions of the Mercedes EQS rival are being measured. Test and development engineers evaluate the motor and rolling noise, along with vibrations and aeroacoustics. Even the mandatory pedestrian protection sound is being fine-tuned, as are the artificial "engine" noises inside, co-developed with Hollywood film music composer Hans Zimmer.

Gallery: 2023 BMW i7 undergoes acoustic testing

With the i7, BMW has acoustically optimised the electric drivetrain by developing a bespoke mount for the electric motors. These have a specific noise encapsulation to guarantee a silent operation, enhanced by installing a foam absorber in the tyres. Body rigidity at the front is also up compared to previous 7 Series generations, while the flush door handles diminish wind noise.

For the same purpose, the 2023 BMW i7 will have aero-optimised side mirror caps (why not cameras though?) and a nearly closed underbody. In addition, the luxobarge has been shaped in such a way as to have clear-cut body surfaces. These changes also pay dividends in terms of range by lowering air resistance.

BMW will unveil the 7 Series and i7 in the coming months, with the range-topping ICE model believed to be a 760i with over 600 bhp from a V8 engine.