Seems like faster bows, lighter arrows, lighter strings and poor releases (plucking) can all help make more noise, but some bows are by design quieter than others. My Widow and Morrison recurves aren't what I'd call noisy, but they are louder than my Super Shrew, and all three are louder than my Hill Big Five and Abbott. Aside from proper arrow spine, using heavier arrows and adding more weight/mass to the string (via a heavier string or higher mass silencers) can help turn loud to dull. Silencer location can also help. I use tied-on catwhiskers alot and like their water resistance, movability and performance, but a thick yarn puff may be the quietest overall particularly when left large and wrapped around the string for an inch or three. The thing I don't like about the large puffs though, especially in lighter colors, is how visible they are as the bow moves...sort of like floating tennis balls. They tend to flash a bit, not unlike a bowquiver full of bright fletching waving around. Not always critical, but definately a potential problem for close-range shot opportunities.
Lots of stuff contributes to loud bows and blown shots. The devils' in the details.