If there’s a lesson to be had from these first and most recent recordings of Elektra, made 66 years apart, it’s that the opera isn’t becoming any more approachable. Even amid rising orchestral standards, top players say that every page of the score looks like a violin concerto. As for singers, Birgit Nilsson appears to be a freak of nature, a vocalist who could sing the role, not just survive it. In fact, the strain of performing Elektra can seem like an intended part of Strauss’s dramaturgy in this dense, harmonically unstable characterisation of Sophocles’s ancient revenge tale, in which the title-character waits for her long-absent brother Orestes to avenge the death of her father. But strain is largely absent in the 1944 Hamburg recording, made with the benefit of then-recently invented tape-recording technology. The opera’s surface hysteria is secondary to clarity of utterance, and what a pleasure that is.

In our times, words tend to recede into a clarion vocal sound, but here, words define the sound in a studio recording that doesn’t require the singers to be heard over an orchestra, and has them positioned in very close proximity to the microphones. Singers, orchestra and conductor all seem to have the opera in their bones, projecting a sense that they’re living the piece. The long monologues thus have greater detail. Perhaps more unusually, however, the famous Recognition Scene, in which Elektra and Orestes meet for the first time in years, has a genuine sense of emotional interaction between the two singers.

By any standard, the Hamburg cast is at a high level. Erna Schlüter was rightly considered one of the best Elektras of her time, Annelies Kupper brings true dimension to the less-than-fascinating role of Chrysothemis, and Gusta Hammer actually sings the oft-declaimed role of Klytemnestra more than any other on disc. Robert Hager’s Wagnerian Orestes is dominated by an exceptionally grim sense of the assassination duties that lie before him.

In contrast to Thomas Beecham’s live 1947 Elektra on Myto (also featuring Schlüter), Eugen Jochum doesn’t really hear much kinship between the orchestration and Strauss’s more sensuous Salome. Maybe it was the time in which the recording was made (by June 1944, Germany was an anxious place), but Jochum’s approach is dominated by nervous rhythm and a general sense that the opera occupies a unique sound world in the composer’s output. One major drawback is that the orchestra seems somewhat recessed: the eerie Wagner tubas that accompany Orestes, for example, don’t make their full effect. As historic recordings go, though, this one isn’t just a valuable document but offers plenty of pleasure; this particular incarnation of it sounds as good as any.

Skipping forward to 2010, Valery Gergiev was clearly born to conduct Elektra, and not just because of his trademark animal energy. Whatever the technical complexity behind the score, Gergiev has the LSO sailing through metre- and key-changes with almost effortless fluidity, and Strauss’s dramaturgical acumen has never seemed clearer.

The singing is a bit of a shriekfest. Some of the more heated exchanges between Elektra and Chrysothemis are barely intelligible. Jeanne-Michèle Charbonnet generates plenty of manic excitement with her ultra-aggressive vibrato but in some later scenes sounds strangely underpowered (fatigue?). Underneath all that, there are many signs of considerable theatrical intelligence; at times, her conviction triumphs over her own voice. As Chrysothemis, Angela Denoke sings well enough but doesn’t seem particularly gripped by her role. Dame Felicity Palmer’s Klytemnestra is one of the few that actually sounds motherly; her voice is lighter than the soon-to-retire Wagnerians one often hears in this role, but her formidable rhetoric gives her all the necessary conviction. Matthias Goerne is the one vocal marvel here: his Orestes has nobility and morality unclouded by the toxicity of his sister’s obsessive need for revenge.