Drum shells can carry an inherent ringing overtone quality depending on the material type, construction method and the dimensions of the shell. For example, fiberglass drums are known to be a bit louder, but usually have a lot of ring. The tonal quality of the drum shell itself can be heard by removing the head, placing your ear next to the shell and LIGHTLY knocking on the drum shell. Be careful because the tone can be very loud right in your ear!
Matching skins to the tonal qualities of the shell is very important in getting the purest sound from the drum. For drums with more high end overtones or rings, a thicker, lower density skin is often preferred. This would include thicker steer white steer, or cow. For drums with a dryer sound, a more lively skin can be used to pull out more tone, sustain and volume from the shell. Medium or medium/thick steer, cow or camel skins are a good choice for this, depending on the size of the drum.