I've been considering buying some big copper tubing and cutting it to 12 different chimes as something for my drummer to use. I would like something in the 2 to 4 octave -- around the A or D string of my bass. Is this practical with the tubing that would be necessary? Also, is there a formula to calculate the frequency based on the circumference and length of the tubing so I'm not going in blind trying to tune it? Can somebody give me a handy run down of the different ratios for all 12 chromatic notes? I'm pretty sure the A I'd want would be at 110hz, so I think I could start from there. Also, what materials would anybody recommend? I was thinking copper tubing?