This is a nice YouTube video that shows the effects of a suppressor:
It’s a Glock 19 with a suppressor on it. 10 rounds are fired. The first 5 are 115 grain bullets and the second 5 are 147 grain bullets. The reason that matters is 115 grain 9mm rounds tend to go maybe 1200 feet per second, which is faster than the speed of sound; whereas 147 grain tend to go slower than the speed of sound (900-1000 fps). While a suppressor can do something about the escaping gases, it can’t do anything about bullets breaking the sound barrier, going supersonic, and creating the sonic boom (the crack).
Suppressors are wonderful things. Helps to save your ears, helps to keep your neighbors happy.
Stuff From Hsoi 
That’s quite an obvious difference. Too bad the cost to own one outweighs it’s usefulness for me. 😦
I don’t know. All depends on your use I guess. For instance, hunting for feral hogs at night? Suppressor plus subsonic ammo is very useful there. Keeps your neighbors from being bothered. The local night hog hunt guys use ’em for just such a reason… else you could imagine the phone calls the local sheriff and game warden would be receiving all the time. 🙂
And that is exactly it – suppressors are not the vacuum-of-noise-inducing devices htat the television shows and movies would have you believe. They have very distinct limits, and they still sound like a firearm going off… just a lot quieter.
Of course, the funny thing in all of this is that I would face a hefty fine if I toodled my internal combustion device down the road without a suppressor on it. On the flip side, if I took my other internal combustion device to the range with a hearing-protecting muffler on it, I could be sent to jail for a very long time.
Ah, the oddities of modern “government”.
but remember… they’re here to protect us (from ourselves).