Not necessarily. It's not quite that simple.
High-velocity and hyper-velocity ammo is usually loaded with slower-burning powder that creates more muzzle blast when fired out of a short pistol barrel. However, a longer barrel will allow the bullet to go supersonic, which will cause a telltale "crack" even if the firearm is suppressed. For example, only the hottest hyper-velocity loads will actually go supersonic from my 4" S&W M18, but high- and hyper-velocity loads have noticeably more muzzle blast than a standard-velocity or subsonic load due to the type of powder.
Actually it is that simple. Whether you have a fast powder or a slow powder, the longer barrel gives it more time to burn and makes for less muzzle blast. If the powder was optimized for a 5" barrel the pressure would have dropped considerably by the time the bullet leaves a 24" barrel. If the powder is optimized for a 16" barrel , it will only be half burnt in a 5 inch barrel while it is still is below peak pressure exiting the 24 inch barrel. In either case, the 24" barrel has less muzzle blast.
I have shot everything from subsonic target loads to hypervelocity loads out of both guns, and the longer barrel always has less muzzle blast. There is a very distinct difference between remington subsonics and CCI stingers out of the rifle, but the same could be said for the pistol. There might even be a case where one load is louder in the rifle than a different load is in the pistol, but as long as you compare apples to apples the longer barrel is quieter.
I'm not saying that a 5" barrel will be noticebly quieter than a 4" barrel, I'm just saying that the rule of thumb is that longer barrels are quieter. If you want to set yourself up with the quietest .22 possible, you need to pick the right load and a long barrel.