One of the most interesting lines of thought:

Architecture as a Musical Instrument

The architecture of a musical instrument relies on both materiality and enclosure of a defined space for sound to be able to resonate throughout the body of the instrument. If architecture is seen as a musical instrument, then the sounds that are generated and manipulated within the space becomes a participant in the whole architectural experience. The important factor in this method is acoustics.

For more on this method, please refer to Steen Eiler Rasmussen’s Experiencing Architecture.

More about this proposed classification of the relationships between music and architecture here:

http://suite101.com/article/relationships-between-music-and-architecture-a280916