Week 7

The second print of the dock was completed. It was immediately apparent that the design was unsuccessful; when placed in the dock, it was clear that the speaker was not at all amplified. Preliminary tests, as performed on the case, confirmed this, so no further tests were conducted. To redesign the dock, research was conducted to develop a better model.

The research showed that exponential, parabolic, and hyperbolic shapes are best for reflecting sound waves to amplify them, and also suggested ratios for horn length and mouth and throat area. Reflecting sound waves in these shapes causes sound waves to elongate, increasing the amplitude, which is what is perceived as loudness. The ideal shape of the horn depends on the frequency of the waves. Ideal throat diameter is proportional to frequency, whereas ideal mouth diameter is inversely proportional to frequency. Ideal horn length is given by the following equation, where "A" is defined as area of horn mouth, "a" as horn throat, "f" as frequency, and"L" as horn neck length:

L=(log(A)-log(a))*4000/(f*0.4343)

The stringent parameters of the phone case make it difficult to appease this relationship, but more design liberty is available with the dock. Since music consists of a wide range of frequencies, a horn that works well for a median frequency will be utilized. The next dock will be designed with careful measurements to optimize its amplification ability. In the meantime, another dock was designed and will be available for testing in Week 8. The CAD model for the printing dock is shown below.

CAD of dock design 2