I'm with ya it has to raise db some, the question is how much. I think TBAC had the omega 300 with and without the 3 port anchor brake at the silencer summit and there was significant difference.
Only had 1 day with my scythe thus far on an 18" 6 creed. Previously had a gen 1 ultra 7 on it. I didn't swap them back and forth but just off memory it seemed about on par with the U7, maybe a hair louder but that's a giant WAG because they weren't back to back. Part of it might be that I moved the u7 to a 28" 6.5x47 so with less powder and 10" more barrel shooting back to back that x47 was definitely quieter that day. The Scythe was plenty quiet, i'd have zero reservations using with 1 port anchor brake hunting without ear pro.