Set-up Closed tube with a hole at each end. Microphone at one end attached to computer. Clap noise made at the other end which will produce a range of frequencies. The computer program detects the resonant frequencies and their amplitudes. The graph produced seems to show the lower resonant frequencies to have higher amplitudes and I've read that in musical instruments each new 'generation' of harmonic (increasing node number) has a lower amplitude. On my graph it looks like the amplitude exponentially decays with increasing resonant frequency. Is this correct? Is there an exponential relation that can be seen from wave equations, if so which equation?