In Fartology, the 27th principle clearly states:
Silent farts do not smell the most. It's just that they carry the
surprise factor, which makes them like a fragrant ninja, ambushing
other people's senses when they don't expect it
Please consider buying my book:
Fartology: Science or Art?
Dr. Bartholomew Ivanovich Seitse
Oxford University Press. U.K. 2005
10th Edition.