Another essential aspect of Goebbels' methods comes from the possibility of manipulating what he has, from compositions by other people (as in staged concerts such as Eislermaterial, Erarytjarytjaka, Hashigaraki or in his Hörstücke) to recorded sounds he made himself. As he says:

I'm not a visionary or someone who has a clear idea of what he wants to do, I always react strongly to what I see.

I don't hear music in my head before, I look at what instruments have been created, according to our instructions or the technicians' suggestions, and the possibilities of machines, and then I work with what I have. [1]

This attitude is a consequence to the possibilities given by recording technologies as instruments for producing, not for reproducing, music. Mixing and editing have been compositional tools for rock bands and DJs for many years now, and Heiner Goebbels knows it well (he also worked on mash-ups and remixes in his Hörstücke). Here are three of the five main characteristics about recording as a compositional tool Chris Cutler (who played with Goebbels in Cassiber, Duck & Cover and Cassix) pointed out.

Recording makes possible the manipulation or assembly of sound, or of actual performances, in an empirical way- that is to say, through listening and subsequent decision-making. […] recording is a medium in which improvisation can be incorporated – or transformed through subsequent work- into composition.

Constructive decisions in the assembly of music are concrete and empirical and can be reached through discussion. A personal vision is no longer the necessary mediator between composition and realisation. This can become a collective activity. [2]

Those elements were at the basis of Cassiber's work, and the main idea of the 'Cassix' project.

Franco Fabbri invited Heiner [Goebbels, Alfred Harth and Chris Cutler] to join three of Stormy Six (Umberto Fiori, Pino Martini and himself) to present a public workshop and recording project as part of Hans Werner Henze's 1984 [3] Montepulciano Cantiere Internazionale D'Arte […] The idea was that the six musicians would divide into all possible pairs (15) and each duo would prepare or improvise a 3 or 4 minutes piece which would then be recorded to 8 track tape. These recordings were subsequently to be treated as raw material for the whole ensemble to work on, using overdubs, editing, composing and processing, the goal being to produce from each beginning a fully fashioned recorded composition. [4]

Cassix's piece "The Stanislavsky Method" was started by Goebbels – as Franco Fabbri remembers – from a sample of a speech by Ronald Reagan, while Franco Fabbri did the same with noises produced by a copy machine ("Copy Machine") [5]. Sampling and 'plunderphonics' [6] are compositional methods of someone who "reacts strongly to what he sees" (or hears), that is, the perfect example of "listening and subsequent decision-making".

Manipulation of recordings is still essential for Goebbels, even in his career a solo 'Composer': here's an excerpt from SHADOW/Landscape with Argonauts. This is one of the hundred voices recorded in the streets of Chicago of people reading – and misreading – a poetry by Heiner Müller translated into English. The prosody, the inflection, and all of the misread words and spoken parts become part of the composition – basically a funky groove – because Goebbels created the musical background after the man read that part of the poetry.

This compositional sensibility is made possible only by multi-tracking technologies. The whole idea of manipulating musical materials empirically comes from the possibility of recording. In other words, Goebbels' approach to composition itself would be impossible without it: his sensibility, even when he doesn't work exclusively or explicitly with records, relies on it. The memory of sound – to put it in Cutler's words – is essential to him.