All the writings in Gerhard’s notebooks suggest that the late 1950s was a time in which the composer was undergoing a significant rethinking of his approach to composition – one informed by his serial structuring of time and pitch and the intuitive freedom that working in the electronic medium gave him. Unlike Schaeffer, who wrote extensively about musique concrète in his two major treatises, À la recherche d’une musique concrète (1952) and the Traité des objets musicaux (1966), or other early pioneers such as Stockhausen or Xenakis, Gerhard did not set out to develop new models for listening and composing with sound. Notwithstanding the importance of the Audiomobiles (1960) and the later Sound Observed (1965) radio documentaries Gerhard created for the BBC Third Programme, Gerhard was, as a freelance composer, more interested in composing the next work rather than theorizing about them. This is not to suggest that Gerhard was not an active thinker. In fact, the composer’s notebooks document his ongoing engagement with electronic music – the discourse surrounding it extends over more than a decade. These notes, quotations and short writings consider, among other things, the nature of sound, time, texture, and how working in the studio offered a working practice that was fundamentally different to composing with instruments. These notebook entries were never intended as contributing to a theory of musique concrète, rather they are a document of the composer’s ongoing exploration and questioning of the new medium and its ramifications for all aspects of his creative work. Nevertheless, when these distributed passages are drawn together, a coherent and cohesive body of thought emerges.

One of the first things that Gerhard considered was the medium itself, and how the unchanging nature of the sound material on tape nevertheless resulted in the listener experiencing the work differently each time. The composer writes that,

[…] a Velazquez, a Henry Moore sculpture are as immutably fixed in their being as a piece of sound-composition on tape – or as any record for that matter. They do not change at different viewings. They do not change, be we do, and in more ways than one, both psychologically and sociologically.

The immediate tactility of working with, and transforming, sound with magnetic tape and the subsequent montage process opened up new possibilities for thinking about music as sound – as a temporal flow rather than discrete bars and units. Here a further comparison with Maderna may be drawn. About electronic music, Maderna said, ‘we no longer listen in linear time – our consciousness casts various projections of time that can no longer be represented with the logic of one dimension’. Working with electronic music made Maderna trust his compositional intuition. The influence of electronic music on Maderna’s instrumental composition can be found in works such as the Serenata per un satellite. Gerhard himself wrote that ‘the way time is felt in electronic music differs entirely from the way time is experienced in traditional music’.

Gerhard was well aware of the techniques of electronic music on the continent: transposition, looping and layering of sounds, cutting and splicing to create rhythms or dynamic envelopes, feedback, filters and ring modulators, were thoroughly described in a special number of the technical magazine of the Nordwestdeutschen Runfunk devoted to the Cologne Studio for Electronic Music , part of the composer’s book collection along with other seminal texts relating to the early days of electronic music by composers such as Pierre Schaeffer, Karlheinz Stockhausen and Milton Babbitt. While always suspicious of studios operated by sound technicians, Gerhard, on occasion regretted his lack of more sophisticated devices, envelope controllers and modulators. It is therefore not surprising that one of his favourite resources was the use of transposition.

Gerhard’s approach to electronic music traversed the aesthetic paradigms that polarized early musique concrète and Elektronische Musik, often using instrumental, concrete and – on occasion – electronic sound materials. Working very much on his own initially from 1954, he was critical of the dogmatic approach of his European contemporaries, writing that,

[…] most of us had already noticed for some time that, whether German, Italian, Dutch or Belgian, electronic music sounds curiously alike in its timbral aspect. If the possibilities were really unlimited, one couldn’t help feeling that these composers were strangely coincident and repetitive in the use they made of them.

Gerhard goes on to write that the sine tone has a ‘rigid, cold, dead-signal quality. It is utterly unsuited to convey anything warm, tender, vivid, alive in human experience’. From a compositional perspective, Gerhard was always more interested in the metamorphosis of acoustic source materials and the potential they offered for abstract sound composition, stating that ‘the microphone captures the living spark of the natural acoustic source’. Gerhard was, however, more circumspect than Varèse, Schaeffer or John Cage in his use of acoustic sources often using (extended) instrumental sounds. In his unpublished notebook from 1957, Gerhard writes that he considers that: ‘the term “musique concrète” is ridiculous twice over, first, on its own account: it doesn’t even pretend to name the thing directly; second, it takes for granted that, what is condescendingly called “the other music”, is abstract. Why?’ Later in a script for a radio programme for the BBC Third Programme entitled Audiomobiles, first broadcast in 1960, he wrote that:

[…] in principle, anything that comes from an acoustic source is possible material for musique concrète. This, of course, throws the gates wide open – too wide, perhaps – to material of all sorts, musical and not so musical. The French themselves, for instance, are not above using pots and pans for their exercices aux casseroles as they describe them.

Gerhard script of this radio programme was developed as ‘Concrete Music and Electronic Sound Composition’, presented at the Joint Congress of the International Association of Music Libraries and the Galpin Society in Cambridge in 1959. Deletions in his notebooks reveal an interesting statement left out of the broadcast and the published version:

Instead I’d rather try to briefly characterise in general lines the two schools of thought – musique concrète and electronic music – in order to which have been responsible for the main developments so far – in order to see what room is there left if any, for a third approach whether there is room and justification for a third approach and if so, how this would be related to/and how it would differ from …

Gerhard’s ‘third’ approach to electronic music – with its emphasis on the abstract ‘musical’ quality of concrete sounds rather than their associative meaning, and the sampling and transformation of his own instrumental compositions – is akin both to the work of Iannis Xenakis and Bruno Maderna – two composers for whom electronic music and its techniques were to play an important part in informing their compositional aesthetic, and also to the later writings of Schaeffer. Gerhard’s use of concrete, instrumental and electronic sound sources in Audiomobile 2 ‘DNA in Reflection’ (1963) has a kinship in approach with Maderna’s La Rire (1962) which incorporates the sounds of voices, footsteps in rain, white noise and sine-tone generators, as well as transformed timpani, flute and piccolo – one that demonstrates an openness to all possibilities inherent in the medium rather than the strictures of the early Paris or Cologne schools of thought. Although Gerhard possessed a copy of Schaeffer’s 1952 treatise À la recherche d’une musique concrète and critiques it in his notebooks, it is Schaeffer’s phenomenologically reductionist notion of l’écoute réduite, proposed in his later Traité des objets musicaux (1966) – in which the sound as ‘sign’ is ignored in favour of listening to the abstract contours and dynamic qualities of the sound – that is most akin to Gerhard’s thinking. Schaeffer wrote ‘it is the sound itself that I aim at, that I identify’; two years previous to this on his radio programme Sound Observed, Gerhard himself said that ‘sound does not remind me of something else, it reminds me only of other sounds’. In this respect Gerhard’s approach can be termed proto-acousmatic (Schaeffer defines acousmatic as ‘referring to a sound that one hears without seeing the causes behind it’. )

Such an acousmatic approach enabled Gerhard to focus on the abstract musical potential of the processed sounds and their dynamic shaping over time, a technique not dissimilar from his handling of instrumental material. However, the electronic medium offered a more intuitive approach to music making than Gerhard’s increasingly complex pre-compositional structuring for his instrumental works. At the same time that the composer was finishing one of his most highly structured works, Symphony No. 2 (1957–9) – a work in which the serial set determines not only the pitch content but also the temporal structure of the work – he was also embarking on a series of works in which sound composition played an increasingly important and liberating part. These include the Audiomobiles series, Lament for the Death of a Bullfighter, Caligula, the taped sections of Symphony No. 3 ‘Collages’, as well as the radio and theatre productions The Overcoat, Pericles, Macbeth and the Prix-Italia-winning The Anger of Achilles.