I doubt you'll be able to tell much difference as the shooter, but I can definately tell the difference between a shotgun, a rifle and a muzzleloader from a distance. The shotgun makes a deeper rolling boom, while a rifle is a somewhat shorter and higher pitched crack. A ML is in between.

But as far as your neighbors are concerned, if the sound of gunfire disturbs them, the difference in pitch and tonal quality isn't going to make any difference. I'm guessing that they'll care more about the number and frequency of the shots fired, more than the dB level of the noise. So unless you're planning on putting a lot of rounds down range I doubt they'll take much notice.

Mike