How Do Different Aperture Shapes in a Styrofoam Box Affect Wave Harmonics?

[arianna1012]

I did an experiment for school, and I put a speaker in a styrofoam box with a rectangle cut out of the front. I had styrofoam bricks that fit perfectly in the hole, each with a hole cut out. The hole shape differed, with things like a funnel, a diagonal line, a circle, a square, etc. I was trying to see if it effected the property of the wave, like wavelength, frequency, etc., but after getting my data I realized it actually effected the shape of the wave. Some are sinusoidal, but others have more of a triangle or even a square shape. I know this is caused by the harmonics, but I need to figure out a way to compare the harmonics from a certain block to the other blocks. How do I do this?

 

[Pythagorean]

The only thing that varies with different shaped holes is the scale of the spatial dimensions. How would you measure the spatial dimensions of a wave and how does it compare to the spatial dimensions of the apparatus?