4.8. Acoustic transformers
As for the other acoustical elements, there is no configuration of materials that will act as a “lumped” transformer over a wide frequency range. Also, what may appear to be an acoustic transformer when impedances are written as mechanical impedances may not appear to be one when written as acoustic impedances, and vice versa. As an example of this situation, let us investigate the case of a simple discontinuity in a pipe carrying an acoustic wave.
Junction of two pipes of different areas
A junction of two pipes of different areas is equivalent to a discontinuity in the area of a single pipe (see Fig. 4.9a
If we assume that the diameter of the larger pipe is less than λ/16, then we may write the following two ...