On the eve of the Scottish Referendum, and in the the church where John Knox was ordained as a Catholic priest before spearheading the 1560 Scottish Reformation, we enjoyed an evening of distraction from division courtesy of Russian Orthodox liturgical music. At a glance the 16-item programme might have appeared one dimensional in its near singularity of language, raison d'être, and a cappella delivery – often of repeated texts. However, it soon became clear that this was to be more of a whisky tasting than repeated sipping form the same chalice.

Beginning at the rear of the church, Tenebrae, directed by founder Nigel Short, opened with three numbers drawn from Rachmaninov's 1910 Liturgy of St John Chrystosom) Op.31 and his 1915 All-Night Vigil Op.37. The Cantor, bass singer Adrian Peacock, delivered his responsorial prompt “Mirom Gospodu pomolimsya” (In peace let us pray to The Lord) from the central aisle; the choir's reply, “Gospodi, pomiluy” (Lord, have mercy) came from the side aisles. During the response, Peacock moved forward a few paces, stopping in time for his next phrase. One such pause landed him at my side and I could feel my ribs resonate with his voice; this was more a matter of depth and richness than simple volume as the solemnity of the moment did not merit a forte dynamic.

The profoundly deep reach of Tenebrae's five-man bass section registered in more than simply sensational ways; the contrast of mood available by variety of vocal range in the choral writing was certainly enlivened by this feature. Amongst the most striking examples was Nikolai Golovanov's Slava Ottsu (Glory to the Father) which, having begun with voices quite close together, quickly opened out into a strikingly wide texture. By the second line an impressionistic sensibility was beginning to emerge in the harmonisation of “veki vekov” (the ages of ages). The balance across chords was excellent and, enhanced by the wonderful acoustic of St Mary's, it was possible to follow the drama inherent in the tensions and resolutions of each part, and its contribution to the whole.

Expression of the harmonies was a fascinating element in the performance. For the most part chromaticism was employed and expressed in the manner suggested by the term – imply to provide colour, as opposed to, say, Wagnerian subsidence. That said, there were moments of genuine surprise, notably in Rachmaninov's Cherubic Hymn (one of four settings in the programme). The text's triple Alliluya was no simple, affirmative closure but an extended farewell by ascension in which the inclusion, and delivery, of one chromatic note produced a moment of fleeting ecstasy. For the most part the music communicated by disarmingly simple means such as the joyously delivered harmonies over pedal notes in Kalinnikov's Gladsome Light.

Control of dynamics was excellent across the programme and before long, a logical pattern began to emerge. Reverential moments were suitably hushed but glory – rarely a quiet phenomenon – prompted some electrifying crescendos. Moreover, the protracted descent from some of these, for example in Rachmaninov's Bogoroditse Devo (Rejoice, O Virgin) was always beautifully controlled.

Dynamic variety was also afforded by a variety of other means such as reducing forces from eighteen to eleven or using a single gender, such as in Pavel Chesnokov's setting of the Cherubic Hymn which used only women's voices in some affecting and serenely performed two- and three-part writing.

Nikolai Kedrov's setting of the Ochte Nash (Our Father) was a haunting example of the power of that doubly elusive phenomenon - the beautifully simple delivered simply. Its relatively unadventurous harmonies were beautifully balanced, all at low volume, which made the segue into Rachmaninov's bracing Vzbrannoy voyevode pobeditelnaya (To Thee, O Victorious Leader) all the more startling.

Tchaikovsky's English language Legend (The Crown of Roses) was a linguistic and musical sorbet notwithstanding the text's prescient tenebrism of child Jesus' briery and bloody bullying at the hands of his peers.

The unforgettable moment of the evening for me was Chesnokov's Tebe poyem (We hymn Thee) – the first time I can recall seeing "hymn" as a verb. As this preceded the second half's processional Litany of Supplication (Rachmaninov) it was sung from the rear of the the church. Robbed of the power of sight, or perhaps relieved of its distraction, it was a delight to let the ears reach into and reside in this short piece's tender harmonies. The sound was deeply affecting - literally, as it was underpinned by some of the evening's lowest notes - at one point down to an A below the bass clef! This choir simply has to be heard to be believed, if possible in an acoustic such as this.