Our favourite piece of product design from last week's D&AD New Blood multi-institution grad show was Michael Harper's BeatCity – and it was the only one that's I'd describe as having commercial appeal in its current, fully-finished form. BeatCity a series of speakers for use with mobile phones such as the iPhone in the shape of buildings. Each building represents a different type of music from the already-architecturally named House and Garage to the more symbolic Heavy Metal – and Michael displayed them as complete city on a street with trees and streetlights (right).

The houses are intricately and harmoniously designed – but most of all they're great fun and just the type of thing I could see sold through Bouf or Made in Design (and on a acoustically appropriate shelf in my house).

As well as designing a pleasing product, Michael clearly has one eye trained on the practicalities of distribution and promotion. Each house is laser cut from a single sheet of wood into pieces, which would be packaged flat for cheaper distribution and shipping. The buyer would pop together the components to build it themselves.

Alongside the speakers, Michael has designed the concept for an accompanying iPhone app, which would allow higher-end buyers to order a customised house – the kind of service that's as important for good PR as it is for the revenue it brings.

We caught up with Michael to find out how he designed the houses and what his plans are to turn these into real products. Use the slideshow controls above and right to read the interview and see more photos of Beat City's design and development.