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Pitch in terms of tube length
Posted: Fri Oct 13, 2006 7:34 pm
by jbeish
Hi all- Just wondering if anyone could point me in the direction of finding a source for the length of tubing needed to produce a certain pitch i.e. an F tuba is 9 feet long there an F is 9 feet long... I'm working on a project for a class and our group would like to build an instrument like those used in the Blue Man Group. Thanks!
Justin
Re: Pitch in terms of tube length
Posted: Fri Oct 13, 2006 7:38 pm
by Chuck(G)
jbeish wrote:Hi all- Just wondering if anyone could point me in the direction of finding a source for the length of tubing needed to produce a certain pitch i.e. an F tuba is 9 feet long there an F is 9 feet long... I'm working on a project for a class and our group would like to build an instrument like those used in the Blue Man Group. Thanks!
Justin
Go here:
http://www.bias.at/index_e.htm
Click "products" and download and install the Musical Calculator and then bore all your firends with useless knowledge.
Posted: Fri Oct 13, 2006 11:20 pm
by DonShirer
Jbeish, if you want to delve a little deeper into this, you may want to check an elementary physics book. Many of the blue man instruments seem to be made out of cylindrical PVC tubing. The formula for the fundamental frequency (pitch) of a cylindrical pipe open at both ends is f1= c/2L, and for a cylindrical pipe closed at one end (as it would be if you buzzed it with your mouth) the lowest resonant frequency is f1=c/4L. In each case c is the speed of sound (about 1100 ft/sec at room temperature) and L is the length of the tube (plus a small correction of about the tube diameter to account for the expansion of sound waves near the end of the tube). A frequency of 440 Hz, 220 Hz, 110 Hz, etc. corresponds to a musical pitch of A. You can find frequency tables for other pitches in reference books.
You should be aware that tubas are not cylindrical pipes, and will have lengths differing from these formulas somewhat. If you are in a mood to experiment, just buy a PVC pipe from your local hardware store, buzz it and compare it with a piano. Cut lengths off to raise the pitch. If you use PVC elbows to fold up the pipes, be sure to include their interior lengths in your calculations. Have fun!
Posted: Sat Oct 14, 2006 6:51 pm
by iiipopes
And an f tuba is not nine feet long. Trombones, euphs and baris are 9 feet long. F tubas are about 12 feet long, Eb 13 1/2, CC 16 and BBb 18.