Marketers are criticized for not understanding the steps in the engineering research and development process and the challenges of manufacturing a new product at a profit. Engineers are criticized for not considering the marketability of and customer interest in such a product during the planning stages. With the development of 3D printing, rapid prototyping at a reasonable cost may help to overcome the "sound barriers" between the two disciplines. We report on how a cross-discipline class team, using the stage gate model taught by an engineering professor and a marketing professor, helped both groups of students acquire cross-functional knowledge of marketing and engineering design to hear the voice of the customer while creating and prototyping an innovative new product. We provide in detail the work students completed at each stage and explain how developing rough prototypes and testing customer reaction to them lead to 3D printing of an alpha prototype. With an alpha prototype, which looks and functions like a marketable product, students were able to get more authentic customer feedback about their new product.