Mikrophonie I is a piece for electroacoustic tam tam with extremely directional microphones investigating normally inaudible vibrations. It uses six performers: two play the tam-tam with a variety of implements, while two use hand-held microphones to amplify the tam-tam in specific ways. The other two are seated in the audience, filtering the sounds through resonant bandpass filters and dispersing them to quadrophonic speakers. Notable sources of sound are scraping the tam tam, using the tam tam as a resonator for stringed instruments, drumming the tam tam, speaking into the microphones and crunching up plastic.
Stockhausen had his own tam tam, bought for use in Momente, which he had interacted with at home with a microphone and a collaborator interacting with the electronics. His experimentation led to him categorising the sounds into various sound types, with specific actions against the instrument devised to create these sounds. This allowed for a scored-out manipulation of the tam tam.
Mikrophonie I explores a huge variety of textures in its 25-ish minute duration over 33 "moments", a type of structural block Stockhausen described as having its own unique character. The way moments are connected in this piece can vary, with consecutive section not necessarily being dissimilar or in any way related, leading to variations in structural direction; the piece can go to a totally different place at any time, or it can build on what is already occuring, leading to an organically varied structure.
The categorisation of a single instrument in this piece into 36 different types of sounds by Stockhausen, even before any electronic manipulation, demonstrates the massively multitudinous range of sounds possible from electroacoustics beautifully. With so much variation in musical material from a single resonant body, imagine the pot