Frequencies [Hz]

For a long time the avant-garde has taken pleasure in disrupting dreams of audio-visual harmony. Around 1913 the Italian painter Luigi Russolo made his first Futurist experiments with funnel-shaped boxes which emitted nerve-shattering whistles and explosive blasts, and during his presentations scuffles with the audience were common. 'Frequencies [Hz]', curated by Jesper N. Jørgensen, had little to do with the old dream of synaesthetic congruence and a lot to do with sound interference and sensual disorientation. The 14 artists all grew up after the heyday of Cagean Zen and Fluxus theatricality, and for most of them couplings of sound and vision have the matter-of-fact character of a physics lecture. Pure sine tones and subsonic vibrations, oscillographs and glass flasks dominated the Minimalist meander of white wall modules designed for the show.

Franz Pomassl needed only an empty space. In the rotunda of the building he installed a subwoofer system that emanated an ultra-low sine-wave (Rotunda, 2002). My diaphragm flapped like the walls, and navigating the violent bass territory became a test of courage. Ann Lislegaard found a slightly more subtle way to test the visitor's audio-visual orientation: you could easily have missed her piece altogether. On the mezzanine between two staircases an extra step was seamlessly implanted, which hid a microphone. The footsteps were recorded and then played back a few moments later at the top of the stairs (Four Steps Delayed, 2002). Like an audio equivalent of Dan Graham's video puzzles, the body's presence was dissociated from the body itself, as if it were searching for a new host.

Tommi Grönlund and Petteri Nisunen built small speakers into the parabolic mirrors of two searchlights (Ultrasonic, 1996-2002); one speaker emitted a sine tone of 18,000 Hz, while the other shifted between 16,000 and 40,000, depending on the radiation, measured by a Geiger counter. In the space between the speakers, the interference of the two frequencies - the sonic flutter - changed accordingly. With an equally proto-scientific sobriety Carl Michael von Hausswolff demonstrated how the frequencies of the power supply system of the building could be made audible in the room and visualized on an oscillograph. But with both works what you really worried about were not physical explanations but evil radiation, hearing loss and other invisible dangers.

It was impossible not to feel a bit like a laboratory rat: here stimulus, there reaction. Whether the attempt was to abstract 'pure' sine tones or to transmit the unedited signals of the electrical world, many of the pieces in the show came dangerously close to suggesting scientific verifiability, making the visual form little more than an instrument of illustration. The title of Hausswolff's piece - Parasitic Electronic Seance (1997-2002) - suggested a way out of the dilemma: once you admit that model experiments can get out of control and allow the unforeseen to happen, it becomes apparent that what makes the oscillograph's curve quiver could just as well be a poltergeist. At least, a small dose of the supernatural provides a good antidote to the noble gravity of science.

Carsten Nicolai's Frozen Water (2001-2) - two large glass flasks in which the surface of the water is put into a steady vibration by a low bass - could well take some experimental insanity to break its calm perfection. Nicolai, however, compiled the exhibition's fringe programme and displayed an obvious affection for lunatic noise, gathering anyone - from Farmersmanual to Ryoji Ikeda - who has ever inspired anyone else to dance to interference blips. On the opening night a musical presentation by Russell Haswell, who lay on the floor in front of his Powerbook like a sulky adolescent playing in his room, tormented the audience with rough chunks of ear-splitting digital noise terror, but no scuffle ensued - the calm and collected way in which people moved away proved again how the tradition of avant-garde onslaught has cultivated an indifferent tolerance.

Back at the exhibition, with ears ringing after hours of 'pure' frequency, the funky bass lines of Angela Bulloch's Geometric Audio Merge (2002) felt like an encounter with the unexpected. Turning nine of her custom-made light-boxes upwards so that their ever-changing colour patterns immediately evoked the idea of a Saturday Night Fever dance floor, the cliché of disco hedonism was a welcome 'figurative' intrusion into the arctic sparseness of the abstract soundscapes.