The Gershwins would doubtless have been flattered that so iconic a figure as Nikolaus Harnoncourt had taken up Porgy and Bess. George would certainly have blushed gratefully at the parallels Harnoncourt draws with Berg’s Wozzeck in the booklet notes. But, notwithstanding their illustrious namesake, what on earth would have been his reaction to the presence of the Arnold Schoenberg Choir?

If there’s one thing about this emphatically black or as we now say African-American opera that cannot be denied it is its sense of community. It may have been written by two whiter-than-white Jewish boys with their eyes on the main chance but they more than most could relate to the feelings of alienation and injustice and pride in one’s own identity that is at the heart of this fable. It seems to me not just unacceptable but slightly offensive to use a white chorus for a piece in which that sense of an all-embracing community is not just desirable but absolutely central. This is one opera about which you cannot be colour-blind and I am frankly amazed that the Gershwin Estate sanctioned the decision and more than a little surprised that Harnoncourt thought it musically viable. Put simply, the sound and attitude of a black chorus is completely different. Recent live performances from the Cape Town Opera demonstrated that beyond all reasonable doubt and had I put this recording into the player without identifying the source, the anomaly would have struck me forcibly from the moment voices were raised in collective fervour in the opera’s second scene: Robbins’ wake.

That scene ends with the upbeat spiritual “Oh, the Train is at the Station” and good as we know the Arnold Schoenberg Choir are, the swing and ring of the vernacular is a world away. It’s the same in the picnic and storm scenes and even if you are less sensitive and picky about it than I am you’ll surely agree that the choral contribution to “It Ain’t Necessarily So” is so “white” it’s embarrassing.

So, the chorus issue apart, how does Harnoncourt measure up to a score that has clearly been a part of his musical experience for longer than we might have imagined? Well, of course, he relates strongly to its harmonic sophistication and points up its system of leitmotifs and thematic interrelations cleanly and characterfully. The Chamber Orchestra of Europe doesn’t put a foot wrong. But it’s that indefinable “extra distance” in the big emotive moments that can find Harnoncourt and his band a little wanting. Sometimes it’s simply a case of too cautious: like the opening, where the shock of those feverish violins and xylophone would feel that much more theatrical if the tempo were pushed by just a hair’s breadth. And then the slightly truncated “Jasbo Brown Blues” – the second big surprise – which should drop us into an entirely different world of sound and style. But here it’s too straight, too much in tempo to convey the ethnic down-and-dirty feel that Gershwin clearly intended. Similarly the drummings on Kittiwah Island are a bit regulated. And I would certainly have pushed the soulful Broadway trumpets more as Bess enters Porgy’s room at the end of Act I, Scene One. Harnoncourt does, though, give us the atmosphere-setting “Symphony of Noise” into the final scene – a kind of percussive collage of the daily grind which Gershwin introduced as an experimental improvisation at the first performance. This is very much an addition, countering judicious omissions. The score always needed cutting – Gershwin knew that as well as anybody.

The casting is not as consistently spot-on as it was in the celebrated Rattle/Glyndebourne recording (EMI, 6/89). Jonathan Lemalu is Porgy and while one cannot but respond to this artist’s big heart and the warm and intuitive way he connects with the text, the voice itself is troubled by a disfiguring vibrato that seems to grow more, not less, intrusive as the opera unfolds. It’s not always easy to hear exactly what note he is singing. Isabelle Kabatu, his Bess, is smoky and voluptuous, spelling trouble big-time in “What you want wid Bess” where she doth protest too much to Crown. He is the craggy-voiced Gregg Baker from the Ratttle recording, still sounding just as mean and intimidating. And there’s a surprise, a blast from the past, in the casting of Roberta Alexander as the feistily “rapping” Maria. You need the text to follow her words, though.

Bibiana Nwobilo gets the “Summertime” plum but to my ears doesn’t quite nail the intonation – this number has to sound so true and free – while Angela Renée Simpson’s Serena has the gospel fervour going good and strong and delivers stonking climaxes to “My Man’s Gone Now” and “Doctor Jesus” in the Act II storm.

And what of the devil himself – Sportin’ Life? Not enough Broadway pizzazz for me. “It Ain’t Necessarily So” is fine until his legit tenor voice kicks in (more intrusive vibrato) but “There’s a Boat Dat’s Leavin’ Soon for New York” is a let-down at this climactic point in the show – poorly tuned and uncharismatic. At least Harnoncourt gives his trumpets their head in the big band reprise.

In sum, disappointment outweighs enjoyment for me. There is nothing here that constitutes a new or surprising way of looking at Porgy and Bess and, in the matter of the chorus, quite the reverse.