Quality Function Deployment (QFD) is a structured approach to defining customer needs or requirements and translating them into specific plans to produce products to meet those needs. The “voice of the customer” is the term to describe these stated and unstated customer needs or requirements.
A good video which can help to understand QFD ..
Griffin paper on the Voice of the Customer
Click here for the HBR paper on House of Quality by Hauser and Clausing ..