its debut performance in conjunction with the Philadelphia Virtuoso Chamber Orchestra on Thursday night last, repeated its success on Saturday night, though not, it must be said, instantly.

To western ears raised in the tradition of European music, which includes both melody and rhythm, the initial response to a programme devoted almost exclusively to percussion was polite but lukewarm.

By evening's end, however, the audience realised that it had been coaxed into an incredible world where the possibilities of rhythm and sound through percussion were not only infinite but intriguing, and responded with enthusiasm.

Indeed, this was a journey of endless fascinating nuances, stunning multi-cultural "layering,'' and many surprises -- all thanks to four very talented young men who, with their amazing collection of conventional, ethnic and even bizarre instruments, provided the most expert of explorations.

In the opening work, `33 Samra Zabobra (1922),' Brazilian composer Carlos Stasi evokes the myriad sounds of a rain forest. To the insistent rhythms of "scrapers'' are added a strange assortment of sounds using everything from PVC piping to the bow of a stringed instrument rubbed against a cymbal.

Bordering at times on the tedious, it was aptly summed up by the artist who announced, "This is a journey for those who love the weird!'' Next came Peter Garland's `Apple Blossom.' Written in 1972, and based on a 13-note chord, it was played by the group on concert marimba. If short on excitement, it was longer on portraying just how subtle colour changes can be wrought by skillful musicianship.

`Rite Rhythm,' completed by Samir Chatterjee last year, was altogether more lively. Employing various ethnic drums, as well as maracas, a tambourine, and marimbas, it was both visually and aurally stimulating.

As their fingers and hands worked the instruments, at times with dazzling speed, so unfolded a wonderful performance which left the listener in awe.

With `Rhythm Song,' Ethos concluded its group performance with its own arrangement of fellow American percussionist Paul Smadbeck's original work for solo marimba, written in 1984.

Influenced by Smadbeck's experiences to Africa, it proved to be yet another attractive example of cross-cultural music.

Finally, came the much-heralded `Missa Luba Mass' in which Ethos joined the local choir Word, directed by Mr. Lloyd Matthew.

A traditional mass sung in Ghanaian style, its performance was outstanding.

The combination of musicians and singers was both different and exciting, and as the soloist, tenor Dr. Gary Burgess was once more a joy to hear.

As always, Mr. Matthews' meticulous direction led to immaculate diction and timing throughout which, when added to the musicianship of Ethos, produced a truly memorable collaboration.

Nancy Acton