What is the quietest speedcube?

In this video I test a range of speedcubes to try to determine which is the quietest, parents sometimes ask me at competition stalls for a quieter cube so that it can be less of a distraction to them when their child is cubing. Obviously I would encourage all parents to not stop their child from cubing but if it is an issue to consider quieter 3x3x3s or higher order puzzles as these are often quieter.