Having allowed a decent interval to elapse since releasing its revelatory recording of Rudolf Kempe’s 1957 Covent Garden Ring cycle (8/08), Testament has now issued this Parsifal from two years later. It is at its finest during the first part of Act 3, where the conductor’s eloquent steadiness, that feeling for the long line that never settles into mere rigidity, is matched by the outstanding blend of sensitivity and strength in the singing of Gottlob Frick.

Frick sang Gurnemanz in Georg Solti’s less-than-ideal studio recording from the early 1970s, when his voice had lost some of the flexibility evident here, and it is fortunate that the recording favours Frick throughout, giving him just the right degree of prominence, even though the balance with the orchestra is variable. There is no disguising the limitations of the mono sound: it is generally unflattering to woodwind and brass, and often deprives the strings of some of the bloom that surfaces now and again under Kempe’s warmly solicitous direction.

Sonic limitations apart, however, it is good to have such an impressive alternative cast to the standard Bayreuth line-up normally heard in recordings from this period. Like Frick, Eberhard Wächter sang his role in a later recording, though the 1961 Vienna State Opera performance under Karajan (not issued until 1991) has many drawbacks and Wächter hit his most compelling form at Covent Garden – impassioned but never hectoring. In June 1959 Karl Leibl was keeping the title-role warm for Jon Vickers: his voice lacks the youthful edge that Parsifal needs, at least before the middle of Act 2, but he avoids the stodginess and blandness that often afflict singers in the part. It’s a pity that the recorded sound, or his positioning relative to microphones, detracts from the impact of the final monologue.

Gerda Lammers is an admirably un-gutteral Kundry, and to have Covent Garden stalwarts Otakar Kraus and Forbes Robinson in the cast reinforces the special qualities of this performance. If you can discount the sonic deficiencies and are prepared to allow a little time for the Kempe touch to make its very particular effect, you will be richly rewarded.