We designed the vehicle to be low noise and at 25 km/h and faster there should be less noise at speed than from a regular bike due to less wind exposure. And due to no chains and softer body the internal sound level should be less than in a standard GF/CF velomobile body.
The sound comes mainly from the three synchronous belts and only the one for the pedal generator is inside the cabin. The belts are covered to reduce noise. The bike also has electric fans but they run only when needed so that sound should not be intimidating.