As an example of cross-disciplinary experimentation, Hemispherics creates a sonic connection between two duos, consisting of an EEG-performer and a musician. The presence of two duos makes more narrative structures possible. The performers can take turns, and respond to each other in a dialogue. In improvisational jazz playing through question-and-answer is well-known, but not often encountered in modular synthesis, let alone in EEG-performance.
The performance space has at its center a large (semi-)rectangular table on which two synthesizers & EEGsynth setups are installed on opposite sides. Chairs for two, three or four people are added, depending how many are needed to operate the equipment. Two audio monitors allow the EEG-performers to monitor their own sound separate from the mix that is presented to the audience through two large speakers. In front of those speakers, two chairs for the EEG-artists are placed. The audience is allowed to sit and move around the perimeter of the installation.
The doubling of performers increases the possible cross-connections between the performers and sonic modalities exponentially. Not only will the performers and musicians connect as a EEG-performer-musician duo, via the music created by the others, this influence crosses over to the other duo as well. In this way, new and more complex systems emerge, and causality become increasingly circular.
Both the audience and the performers experience the increased complexity and heightened sense of interaction of the performative system. This is especially the case because the role of each of the performers in creating the sonic landscape becomes less clear compared to performance setups where the causal chain is simpler. Cause-and-effect can be brought back into focus during the performance by purposeful movement of the EEG-artists within the performative space. Movement of the performers is necessarily limited however, and the majority of the performative dynamics occur within the imaginative space created by the sounds.
The use of two modular synthesizers presents obvious challenges and opportunities for sonic coherency and attunement. For the sake of both the performers and the audience, the performance starts simple, with the pitch of both synthesizers tuned to each other, playing at low volume. The amount of influence that the two EEG-performers have on e.g. pitch and volume is then slowly increased. This gradually establishes a simple neuro-feedback situation in which the EEG-performers can attune to themselves (establishing control of the sound and the right mental attitude), and each other (establishing communication). Later, with increasingly complex modulation of the sound, the attunement include timbre, attack and speed, as well as complex interactions through harmony/dissonance, tonal distance and phase of change. Moments of increased connection are exhilarating for both the performers and the audience, and show a deep musical potential of brain-music-interfaces.