Pinion gearboxes run quietly and without annoying noises. If noises occur and the gearbox shifts correctly, the noises are not coming from the gearbox but likely have another cause elsewhere in the bicycle. Please check connection points such as crank to pedal, seatpost to saddle, handlebar to stem. A dirty belt drive and incorrect belt tension can also cause buzzing or humming. https://pinion.eu/wp-content/uploads/2018/08/180704Pinion-Troubleshooting-EN.pdf