Here is the only DB test I have done. It was on my 09 Ultra 96" non CVO.
Using the new AMA Standard of 45* angle off the muffler tip and 24" back from the muffler tip.
Now bear in mind I have not had my DB meter calibrated in at least 5 uears so the numbers and no where near accurate for actual db, but still a valid comparison to each other. The measurements were taken within an hour of each other.
Stock 09 Ultra Mufflers = 96db Idle 99db steady 2000 rpm
CVO Cans with 1 3/4" Fullsac Cores = 94db Idle 97db steady 2000rpm
The auditable difference was the frequency, the CVO Cans with the Fullsac Baffles were a much lower frequency, much more pleaasant to the ears (Tone) thus contributing to the drop the db level.
So this is one data point.