MUSIC / Unseen but greatly admired: Raymond Monelle on an offstage triumph in Verdi's I due Foscari and onstage performances of Falla and Schubert

One of the most satisfying voices heard in Edinburgh during the last few days was that of the baritone Phillip Joll. In a manner of speaking, we should never have heard him at all, for he stood in vocally for Frederick Burchinal in Scottish Opera's new production of Verdi's I due Foscari; Burchinal, who had bronchitis, acted while Joll sang.

After an absence of several years it was good to have Scottish Opera back in the Festival with their reassuring new musical director Richard Armstrong. However, the sheer quality of Joll's singing slightly destabilised the drama; the two other principals, the Chinese tenor Deng as a stiff and dry- voiced Jacopo Foscari and Katerina Kudriavchenko as a dour Lucrezia, were never able to gain sympathy. That said, the Doge's pathos in Act 1 and his defiance in Act 3 - the designer, Ashley Martin-Davis, put him in a kind of pierrot's costume, evoking the tragic clown - gripped the heart in spite of the separation of character and voice.

The production, by Howard Davies, was straightforward, the sets converting ingeniously from exterior to interior. While there was very little real acting from the principals - the love duet looked like a wrestling match - the force of the concerted finales came across well, with an astonishing blaze of daylight (lighting designer: Alan Burrett) on the eruption of the women into the Council chamber at the end of Act 2. The almost-modern dress (Loredano, sung lukewarmly by Nicolas Cavallier, was in a blazer and flannels with red cravat and Brylcreem) suggested Death in Venice. This was a very useful production of a rarity, even though it worked best on the public, rather than the intimate, scale.

There was singing of another kind in a performance of Falla's El Amor Brujo by the Orquestra de Cambra Teatre Lliure of Barcelona. The forthright, accurate conductor Josep Pons had the idea of getting a real flamenco artist, Ginesa Ortega, to sing the gypsy melodies in this ballet, which was performed in its original version for chamber ensemble.

This sensuous, ferocious, dark-skinned cantaora, with her shouts of florid bravura, brought the house down. But like 14-year-old Juliets and Japanese Cio-Cio-Sans, she was not really right for the job; Falla's music is a portrayal of gypsy music rather than the real thing, and in any case, a non-operatic voice cannot fill the great space of the Usher Hall.

Ortega sang also in El Corregidor y la Molinera, which is the original version of The Three-Cornered Hat, although apparently only half of the score was performed; and Falla's harpsichord concerto was played on the piano by Lluis Vidal. It was, perhaps, a lesson in how to play Spanish music. The tiny orchestra lacked the habitual chamber-music polish, but without the warm sheen of a big string group there was a rawness and looseness that communicated strongly.

Two song recitals revealed the unusual qualities of very special artists. Robert Holl presented a Schubert programme, accompanied by Andras Schiff. His voice - a true bass, rather than a baritone - is an enormous heavyweight instrument, and he eschews eye-contact, scowling resolutely at the floor. The merely poetic or whimsical disappeared in a fathomless brown study, alternately meditative and heroic.

The baritone Thomas Hampson, on the other hand, eagerly addresses and involves his audience. He has an effortless sunny charm; in songs of pain or grief the feeling is evoked rather than felt but in simple blithe lyricism he is at his best, and Grieg's Six Songs, Op 48, were exquisite.