How much louder is a single exhaust?

How loud an exhaust system is more dependent on brand & type of muffler you are running, if you are running resonators or converters or not, than the # of pipes hanging out the rear. You will mainly get a different tone from running true duals vs a single. I'm doing it to be different & drop a few extra pounds. My exhaust will be loud whether I decide singe or duals since I'm not running coverters or resonators.