hmmm... I have almost all the machines dale offers. That being said, they all sound different. I have a standard brass 6 v that is super quiet, kind of like a neotat but the rotary works sounds much more powerful. Now I have 2 springers, 1 aluminum and 1 brass. The aluminum does make some noise and and the brass, is again super quiet. The aluminum, however, is just as quite when unloaded and seems to get louder when tattooing with the machine at certain angels (cant figure out why).

Now for the ID.. I have one and it is almost silent when it is unloaded. But when loaded it does make some noise. However, I wouldnt describe it as rattly, just some noise. Havent really used it for b and g, but do use it for color and works great at 4.5 v-5v. Also, surprisingly, i was doing some solid fill with a 8 round shader and was working great. I then decided to thicken some lines and used the ID just to test its capabilities. It lined with a 8 round shader like nothing !