On Invisible Gold, American composer, musician and academic David Rosenboom explores the interface between the human nervous system and technology, generating music using brainwaves as signal source and electronic devices as medium. This is a physical, spiritual and scientific immersion in the realm of experimental electronica. David Rosenboom has been working for decades in the realm of experimental music. He is a well-credentialed academic with an impressive portfolio and has written extensively about his compositional and theoretical investigations.

This CD features three tracks - original performance recordings made in the seventies that have been digitally converted and reprocessed this release. The first, Portable Gold and the Philosopher's stone uses brainwave signals from 'biofeedback musicians' to trigger electronic devices such as the Holophone - a bank of resonating filters. The 18 minute performance evolves, devolves and resolves depending on the synchrony or lack thereof between the waveforms generated by the individual performers. From the initial drone emerge convolutions that drift in the sonic field, with subtle shifts in harmonic resonance that seem to occur as much in the field of perception of the listener as in the recordings themselves. The second
and third pieces, On Being Invisible, Parts l &ll extend the theoretical realm explored in the first piece, but with a significantly different result. Rosenboom refers to On Being Invisible as being 'a self-organizing, dynamical system, rather than a fixed, musical composition.' This system generates musical changes, predicts the significance with which they may be perceived, and tests for brain signals that either confirm or disconfirm these predictions. The pieces evolve in a far more random and dissonant manner, converging towards order and then diverging away from it. The result is an engrossing if not at times alarming sonic experience.

Invisible Gold is important as a document in the realm of academic and theoretical discourse on experimental music. The sleeve notes further define the theoretical context in which the work was created as well as relating how, when and where the performances were recorded, by whom and with what electronic paraphernalia. This CD is a must have for those
interested in and passionate about the continuing evolution of experimental electronic music. - Michael Shrapnel for indie-cds.com 2006