The sound boxes of Aeschylus

After nearly 2,500 years, the secret of the masks used in ancient Greek drama has been rediscovered. They were not worn just for appearance - as the familiar icon of paired smiley and weepy masks seems to suggest - but were voice-activated sound-boxes whose resonance triggered a state of ecstasy in both actor and audience.

The dramatic effects of the mask were stumbled upon by Thanos Vovolis, a 38-year-old Greek social anthropology graduate who studied costume and mask design at Stockholm's Dramatiska Institutet before taking it up professionally. Vovolis makes exquisitely modelled reproductions of ancient masks from papier mache, and teaches people how to use them. In 1989, however, he felt that he had reached a stalemate in his design of masks: "I was on the point of giving it up. Everything I had discovered about them seemed to hide the truth still further."

Then he saw the Greek actress Mirka Yemendzakis in a performance of Aeschylus's The Persians in Stockholm. She had revived the 150 almost forgotten ritual cries used in ancient Greek drama - usually crassly translated as alases, alacks and woe-woes - whose physiological effect on actors and audience does not seem to have been grasped by literary scholars. The Persians contains about 100 cries - evoi, evan, evai, alali, io, ia, iache, papapape, papapapapape and many more. He watched Yemendzakis giving voice exercises to an actress wearing a mask he had made with traditional pronounced forehead. "Suddenly, the actress felt a powerful resonance in the cavity between the mask and her forehead. She was a little stunned, but enlivened." For Vovolis it was a moment of truth.

The Greeks of the 5th century BC left no written instructions about their science of sound, which Vovolis believes was central to the rituals of the Orphic and Eleusian Mysteries and the cult of Dionysos - which gave rise to Greek drama. The techniques of voice-production would have been taught by priests in secret. But he cites Vitruvius, author in the 1st century BC of the only surviving classical treatise on architecture, who hinted tantalisingly that the auditorium of an amphitheatre could be designed as a resonant cavity producing consonance - that is, overtones. "Consonance," Vitruvius wrote, "is the process whereby due to suitably placed reflecting walls, the voice is supported and strengthened when two identical soundwaves, arriving at the same point at the same time, combine to produce the sum of its effects." He also mentioned ceramic sound reflectors built into the semi-circular rows of seats.

Vovolis surmises that during the ancient Greek plays, especially at the climax of catharsis, when tragic dilemma trips the mind of the audience into a state of transcendence, "the actors' speech would have become more powerful and clear and the entire auditorium would have vibrated with life." In ancient Greek the words theos (god), theatron (theatre) and therapia (therapy) share a common root that can mean, variously, soul, air, breath, pulse or life.

With Mirka Yemendzakis, Vovolis (shown, right, surrounded by some of his creations) now holds 10-day seminars on how to make his masks work. These begin with 15-20 people uttering moans and wails. Mouths gape and eyeballs disappear under eyelids. It takes several days for the chorus to achieve what he calls "a common breath". Then the masks are put on and the harmonisation continues. It sounds like a cross between "overtone" chanting and the throaty reverberations of pundits reciting the ancient Sama-Veda of India. Vovolis explains: "It's a physical experience of catharsis. You feel that your whole body has been cleansed and purified."

It usually takes half an hour or so for an actor to become attuned to a mask, says Vovolis. "First, they have a feeling of death, then find they can breathe. I instruct them not to try to do anything or even think very much, but just to realise that there, behind the mask, is liberation." The same mask can have different physiological effects upon different people, but some effects have become familiar. For example, the site of voice production seems to settle in the pelvic region. There have now been five stage productions of both Greek tragedies and modern plays using Vovolis's masks. "Even the critics remarked on the impact of the sound," he says proudly.

Further information: Foundation for Hellenic Culture, 60 Brook Street, London W1 (0171 499 9826) or Thanos Vovolis, Dora D'Istria 20, 10676 Athens (00 30 1 721 3839)