Ghiaurov's resounding reveille at the start promises great things, fulfilled so far as his own part in them is concerned. Sutherland's arrival raises doubts for even by this date her tone had loosened so that the firmness of one note did not guarantee the next. Each E flat in ''Tacea la notte'' needs a twist of the screwdriver to tighten it up and, though the trills and scales in ''Di tale amor'' are beyond reproach, the tone-quality itself lacks sparkle. Villain Wixell brings his tone into focus during the course of his opening remarks, and by the finely expressive ''Ah, l'amorosa fiamma'' he seems well prepared for the aria of which he is deprived by the off-stage presence of hero Pavarotti. This is clearly meant to excite interest, as his song, ''Deserto sulla terra'', assaults the night air at a magnificent fortissimo setting at naught the poetic, intimate character of the harp accompaniment. Act 2 introduces the fifth of the principals on whom so much of the success of Il trovatore depends. Marilyn Horne is another whose tone had by then lost some of its early firmness, but ''Stride la vampa'' proclaims her unquestionably an Azucena of style and resource.
So the opera is set on a somewhat bumpy course, rising for the drama vividly enacted in Azucena's ''Condotta ell'era in ceppi'' and for her serene ''Ai nostri monti'' (beautifully sung up to the unsteady last note of the solo), sinking as Leonora and Manrico settle for generalized expressions of their various emotions rather than bringing them to specific life. Bonynge characteristically gives spring to the faster rhythms (for instance, of ''Vivra! contende il giubilo'' and the opening chorus of Act 3) but affords no new glimpse of a dark or tender place in the score nor any wider view of its special passion and dignity.
The rival DG version on CD, under Giulini, certainly does that. It also has a nobler Manrico in Domingo, a highly intelligent, distinctive Azucena in Fassbaender who, like Plowright, the Leonora, compares favourably in firmness of voice. The orchestra is more forward and the approach yields much. The reverential slowness of some of the tempos is one of the drawbacks, the churchy acoustic another, and the fact that it takes three CDs may tip the balance in favour of the Decca recording on two. The best Il trovatore is still very probably the 1969 one under Zubin Mehta, with Domingo and Leontyne Price (RCA SER5568/8, 7/70—nla): alas, no Compact Disc.'