Live recordings of Hans Knappertsbusch conducting Parsifal seem to proliferate like stairways in M.C. Escher prints. The high priest of the podium so owned this music in the 1950s and early 1960s that at least a half dozen transfers are in circulation, augmenting his gold standard 1962 Philips release and the historic 1951 reading that inaugurated the post-war Bayreuth Festival.

All share common characteristics: a spacious approach to Wagner’s musical line, great depth of expression and an unforced wash of sound that tenor Jess Thomas likened to a cloud cushioning the voices on stage.  

Each, too, has its quirks, possibly due to Knappertsbusch’s somewhat casual approach to rehearsing. A Myto remastering from the 1961 Bayreuth Festival is generally lighter and more vigorous than some of his earlier accounts but also noticeably mannered in key spots, such as the statements of the faith motif and in the syncopated, rising figures in the prelude to Act 3. The pacing slackens a bit too much before Parsifal’s return in the final act, at which point the forces seem to rally to deliver a stirring finale redolent with themes of rebirth and enlightenment.

Part of the legend surrounding old school maestros such as Knappertsbusch is built on the notion that they saw Wagner’s scores as a series of huge dramatic blocks that could be fused in a way that suspended a sense of time. Leitmotifs inferred plot and structure instead of serving as dramatic tip-offs. The seriousness of purpose didn’t allow for fussy affectations.

In truth, Knappertsbusch took his share of interpretive liberties like lacing in unwritten ritardandi. What’s striking is how echt his improvisational approach sounds. The first act has a wonderful sense of discovery and expectation, with tempi subtly pushed and pulled and capped by a majestic transformation scene and a full throttle statement of the Grail theme. The opening of Act 2 foams and froths with distorted allusions to motifs heard in the first act. Throughout the performance, the “alertness,” for lack of a better word, is more palpable than in latter-day interpretations by say, James Levine, Giuseppe Sinopoli and Daniel Barenboim.

That said, this release isn’t an essential purchase. The 1961 cast is almost identical to the one Philips would record the next year and is presented in thinner monaural sound that doesn’t nearly capture the unique acoustic of the Festspielhaus.

Thomas, making his Bayreuth debut in the title role, has a distinctive, ringing voice and guileless manner that’s quite effective in Act 1. HIs pivotal middle act confrontation with Kundry is not the most dramatic on disc but intelligently played, with a strong sympathetic cord to Amfortas’ suffering. Though Thomas may have been overshadowed by Jon Vickers in this and other roles, his portrayal is top-notch, gaining strength through the evening and sounding fresh decades later.

On disc, Irene Dalis doesn’t come across as a particularly sensuous or overwhelming Kundry—one wishes for more depth of expression in “Ich sah das Kind,” for example—but is technically spot on at the important moments, with a formidable chest voice and a laser-like upper extension that gives an extra piercing quality to “lachte,” describing how she scorned Christ on the cross.

The lower voices are represented by a group of legendary Wagnerians, most of whom have sounded better elsewhere. As Gurnemanz, Hans Hotter transforms himself from wise, occasionally gruff sage into devout acolyte over the long evening by milking every syllable of Wagner’s text but at times sounds quivery and not as commanding as on the Philips disc.

George London’s familiar, anguished Amfortas similarly doesn’t feel as poignant as on either the 1962 or 1951 Knappertsbusch sets, veering into startlingly throaty cries of suffering before Parsifal absolves him near the end of the opera. The imposing Ludwig Weber is alternately wooly and magisterial as Titurel, possibly as a function of stage blocking or microphone placement. Gustav Neidlinger, on the other hand, is ever reliable as a dark and menacing Klingsor, backed by a squadron of Zaubermadchen that includes the young Gundula Janowitz and Anja Silja.

With so many of the principals better represented in their roles elsewhere in the catalogue, it may be hard to come up with a compelling reason to acquire this set other than for historical completeness. Perhaps it serves as a reminder that even with imperfections, certain combinations of artists can sound like they’ve receded into the score for long stretches of time and leave the impression that the music has taken over.

The 1961 Bayreuth Festival was also noteworthy for a controversial new Wieland Wagner staging of Tannhauser that broke the house’s color barrier by featuring Grace Bumbry as Venus—a casting decision that incited protests from neo-Nazis and some segments of the German press. Though a commercial release on Philips captured a compilation of performances from that run with Bumbry and Wolfgang Windgassen, Myto now offers a one-off in mostly adequate sound with two significant cast changes: Victoria de los Angeles replaces Anja Silja as Elisabeth while Dietrich Fischer-Dieskau takes over for Eberhart Waechter as Wolfram.

The performance is a curious mashup of the 1861 Paris version of the opera up to “Geliebter, komm!” that switches to the Dresden edition and briefly reverts back to the Paris music for Venus’ reappearance in the third act. Wolfgang Sawallisch leads a fleet, clear-textured performance that’s oddly deadpan, skating over the mounting tension of the song contest and lacking sufficient expressive detail in the galumphingly earnest final act.

The 24-year-old Bumbry is more commanding than alluring as the mythical goddess, with a burnished sound that’s generally tidier than what she would produce the following year on the Philips commercial release. Fischer-Dieskau, rounding out his Bayreuth career, is suave, introverted and almost detached from his surroundings in “Blick’ ich umher.” He expertly captures the conflicted drama of a chivalric knight captive to his love of Elisabeth in “O du, mein holder Abendstern,” even though softer notes sound thin, possibly due to the microphone placement.

De los Angeles is a fresh-voice Elisabeth, with a wide column of tone that works a bit better for “Dich, teure Halle” than for the solemn Act III prayer “Allmacht’ge Jungfrau.” Windgassen struggles mightily with the title role’s punishing tessitura, overshooting notes and sounding winded in the opening scene before recovering to deliver a laudable, emotional Rome Narrative. Josef Greindl’s nicely etched take on the Landgrave is marred by a noticeable wobble while Franz Crass stands out among the rest of the cast as Biterolf. The Bayreuth chorus is radiant in the pilgrims’ choruses.

The unevenness of the cast makes the release more of a yardstick to measure the 1962 Philips recording and others that came after than an essential purchase. Bumbry fans will love it for the signs of what was to come; others may find that the vigor and folk-like character of the performance overcomes some of the technical imperfections.