A few decades back, Michelangelo’s frescos in the Sistine Chapel underwent a controversial restoration process. New, vivid colours were revealed, radically altering our perceptions of these familiar artworks, and the results were both praised and criticised. In a similar fashion, the performances of Allegri’s Miserere by the Sixteen on their current Queen of Heaven tour offer a fresh look at a familiar piece. Allegri’s best-known composition (though surely not the single most famous choral piece in the world, as director Harry Christophers claimed in a brief address) was originally the exclusive possession of the Papal Choir, and traditionally was performed on Good Friday in the Sistine Chapel. After the 14-year-old Mozart cheekily wrote it down from memory, it became more widely known.

However, what was heard in the Sydney Opera House on Tuesday evening was not the familiar version, with the famous high Cs from the soprano every fourth verse. Instead, a variety of differently ornamented versions of the basic phrase was employed, following recent musicological discovery of Vatican manuscripts that showed varied embellishments. These decorations (or abellamenti) were in fact one of the main draws for the original congregations. Only in the penultimate quartet section did we finally hear the well-known stratospheric ascent to and descent from the top C, and this was further decorated on the final rendition.

Allegri’s 1638 work was the only outlier in a programme which otherwise swung back and forward between the 16th and 21st centuries, focusing exclusively on the output of two notable Catholic composers: Giovanni Pierluigi da Palestrina and James MacMillan. While the MacMillan pieces were stylistically disparate, there was a degree of homogeneity to the various Palestrina selections. Not that this was particularly a cause for complaint, given how well attuned the choir was to the style of the Renaissance master. The opening Kyrie from the Missa Regina coeli (preceded by the originating chant) was smooth as butter, while in the Stabat Mater which closed the first half the singers provided an object lesson in how to shadow musically the emotional inflections in the text, a prayer to the sorrowing Mother at the foot of the cross. In the second half, the opening Regina coeli was enlivened with perky renditions of the figure at the word Resurrexit (he has risen).

Unquestionably one of the most important composers of religious music today, MacMillan’s output as illustrated in the four works on the programme encompasses a variety of influences. In Dominus dabit benignitatem from the Strathclyde Motets, he used a palette similar to Morten Lauridsen and Eric Whitacre i.e. lots of cluster decorations of basic chords, on top of which was laid a free-ranging melody. In Videns Dominus, the Scotch snap figures recalled (intentionally or not) the composer’s native land, as did the use of drones and ornaments in the encore, Sedebit Dominus Rex.

In the second half, MacMillan’s O Radiant Dawn (the only work not in Latin on the programme) was sandwiched between two motets by Palestrina. This was a brilliant bit of programming, as MacMillan employs a neo-Renaissance vocabulary in this piece, so that it was not dissimilar to the sound world of the preceding Vineam meam non custodivi, although more chordal than Palestrina’s typically horizontal conceptions.

The most substantial piece in the second half was MacMillan’s Miserere, which started out with the rich sound of tenors and basses, and gradually rose into the altos and then sopranos. A later section used the same chant intonation as Allegri had in the non-choral parts of his Miserere, testifying to the continuity of tradition within Catholic liturgical music. The lush final section was surmounted by a tune that seemed very familiar, but I couldn’t quite work out what at the time: later I identified it as the Sanctus from the composer’s own congregational St Anne Mass.

While there were many things to enjoy, the performance of the eighteen (sic) singers did not leave me bowled over. It may be that the Concert Hall’s acoustic did them no favours, but within each section not all voices were of same quality, so that without trying one could pick out individuals from the blend. There were fleeting moments of less-than-perfect precision from quartet of soloists in the Allegri, and occasional issues elsewhere, never enough to spoil the performance, but just enough to take the edge off delight. And while the programme was well conceived, one couldn’t help but wish that they had occasionally dared a little more: by the end of the evening, moving though parts had been, I was left feeling that they might have ventured outside their comfort zone a little more.