That's actually pretty much the opposite of how that works. More fans generally mean lower noise as they don't need to run as hard to deliver the same volume of air. Same with larger fans. There is eventually a point where adding more fans hurts rather than helps, but it's probably more fans than you would think. All of this is especially true for watercooling and radiator fans, the more radiator area and associated fans you have the better. My desktop with 3 radiators and 8 radiator fans is quieter than my server with one radiator, 3 radiator fans and 2 case fans, and that's despite the desktop having a higher total heat load.