Overview

Objective

The goal of the project is to design and 3D print in PLA plastic a phone case and dock that mechanically amplify the sound of a factory iPhone 7/8 speaker. The case is intended to be used for daily mobile use of the device, while the dock will be a stationary unit where the phone can be set to play music in one's home as a substitute for a speaker.

Design

The case and dock feature a winding, internal horn to amplify sound. The mouth of the horn begins at the speaker and tapers sharply as it travels up the case, then widens as it curves back to the bottom. The horn opens near the bottom of the case on the opposite side of the speaker, with the mouth significantly larger than the throat. This horn model is known to amplify sound, and can be observed in many products with the same function. The dock works in conjunction with the case, the throat of this horn aligning with the mouth of the other.

Constraints

The phone case must not trap excessive heat, as overheating causes great harm to a smartphone. The bulk of the case should also be minimized; the phone should sit comfortably in one's hand and pocket. Ideally, the case would offer some protection for the phone, but this is not standard for all cases on the market and would be considered a bonus if accomplished.

Concept

The horn shape amplifies sound by reflecting sound waves in a way that increases their amplitude, which is what is perceived as loudness. Mathematical models show that the parabolic and hyperbolic shapes are useful to this process. Other mathematical models show relationships between ideal frequency and the dimensions of the horn. All of these models were utilized in the design process of the case and dock.

Progress

Weekly updates are posted to the blog. Photographs of printing and test results are included, as well as a description of the progress made. A separate page is included that shows progressing CAD models of the case and dock.