I don't know what level of physics you're in, but I'm going to guess that it's Conceptual. In that case, you probably won't have to get too specific with equations and explanatory information from a mathematical standpoint. Just think, (I know you can do it) what besides plastic or an actual drumhead would make a good drum sound? Originally, drums from ancient civilizations would use animal skin as the drum head, but since that probably isn't an option here, let's look at an easily avalible resource: metal. Have you ever heard the sound that an empty paint can or garbage can makes when hit by a stick or other rod of some kind? Depending on how much stuff is inside of the drum, you will get varying levels of resonation, or sharpness. If you have say, a small pillow inside of your drum, the sound will have more bass tones and will resonate less. Also, if you've ever heard steel drums before (originally from the Carribean/Jamaican region) you'll know that certain metals such as steel, tin, or thick aluminum can be bent using a hammer or other pounding tool so that they play melodies. This might be an option for you. Aside from metal, wood can work well for drums, and if all else fails, buy a drumhead from a music shop. You can really apply tension when using professional drumheads. The more tension or less flexible the drum head is, the higher the higher-pitched it will sound and vice versa. Just in case you need to know specifics about tension, it's worth mentioning that tension is a resistance force that acts against (Newton's third law) the force acting upon it with an equal and opposite strength. If you tighten a drumhead with x Newtons of force, the drum will pull back with -x Newtons of force. By playing the drum, you are able to hear how much tension is acting upon the head because the sound waves that it produces are a direct quality of the tension acting upon it. When a loose drum [low tension] is played, it has more flexibility and therefore sends sound waves of lower frequency out into the air when compared to a tight drum [high tension] that has less give to it (causing the drumhead to vibrate back and forth more times per second), sending out sound waves of a higher frequency. Hope that helps a little.