I have a 25 WC MKIII compact and have it tuned to 45 fpe. The Donny FX on the WC is quieter than a unmoderated 25 Marauder. On hand are a Donny FX, Shogun and Ronin to trade between air guns. The Shogun seams to work best but I can't quantify it. With a cheap meter, shooting indoors at 17 yards at a putty box or a box of rubber mulch the target impact is louder, 82-90 db. Also, your ear is sitting on top of slingshot hammer clanging with each pellet making judgement of the overall sound level difficult. Shooting at small game with H&N Hunters, the terminal impact makes a much louder report than the gun.