Standing waves in instruments
Recall that we considered earlier the case
of standing waves on a string:
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Today, let's focus on a different type of
standing wave: the pressure wave in a column of air.
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Take a look at
the nice illustration of standing waves in a tube
Daniel A. Russell.
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Consider the western flute, which is (in very simple terms)
a tube open at both ends.
- The flute in the picture above has a total length of
about L = 100 cm. What should the fundamental frequency
of a flute be?
But flautists can produce much higher frequencies! How?
By opening one or more holes in the body of the tube.
- The flute has one hole at a distance
50 cm from the end of the tube.
If that hole were opened,
what would the frequency be?
But flautists can STILL produce higher frequencies! How?
By opening two or more holes.
- Suppose the flautist opens two holes which
are 40 cm and 45 cm from the mouth end
of the tube. What frequency would resonate now?