‘I haven’t had as much fun as this in days!’ Justin Doyle certainly looks enthusiastic as he speaks to me on Zoom from his score-lined study in North Yorkshire. ‘We conductors are often in danger of spending more time on administrative things like scheduling and trying to keep up with emails, so getting the chance to lift the score down off the shelf and look at it again in the hour before you called has been so exciting. It brings out my inner geek.’

The score in question today is Bach’s Magnificat, the brilliant starburst performed by the 38-year-old composer for his first Christmas in Leipizig in 1723, which the Lancaster-born Doyle has recorded for Harmonia Mundi in Berlin with the choir of which he has been Chief Conductor since 2017, the RIAS Kammerchor, together with the city’s premier baroque orchestra, the Akademie für Alte Musik Berlin. It’s a piece familiar to many, no doubt, but there are plenty of good reasons to re-examine the score in this instance, as instead of recording the more usually heard later reworking of it in D major, Doyle has chosen to present it in its original version in E flat.

The most significant difference between the two is that in the E flat the 12 concise movements setting the famous canticle are interrupted by four extra, non-liturgical movements on specifically Christmas texts – ‘Vom Himmel hoch’, ‘Freut euch und jubiliert’, ‘Gloria in excelsis Deo’ and ‘Virga Jesse floruit’. This was a Leipzig custom Bach inherited from his predecessors and which seems to have died out not long afterwards, perhaps on theological grounds. Doyle feels, however, that they are a definite advantage in a recording. ‘Whenever I perform a Mass setting, I tend to interpolate motets between the movements, which enhance the liturgical structure and give some theological context. You would never have heard the Gloria and Credo next to each other in a service. When you look at Bach’s cantatas you see that the way he wove biblical texts with Lutheran commentary was crucial to his way of creating a bigger structure. Performing his Magnificat without the interpolations retains the sequence of the original canticle, but it wasn’t Bach’s concept. So yes, I really value these interpolations.’

Other differences are less obvious: recorders instead of flutes in the ‘Esurientes’, a solo trumpet instead of an oboe arcing the plainchant over ‘Suscepit Israel’, a little less ornamentation of some vocal lines, and some more spicy harmonies here and there. Doyle confesses he was tempted to combine (as others have) the D major version with the interpolations transposed, but felt it threw up too many other practical niggles about pitch and where the notes lie on the instruments. ‘In actual fact, Bach might have heard it in the same sounding-pitch as what we think of as the D major version – this is a can of worms, to do with different performance pitch levels in Bach’s day, and that’s a long discussion. Short answer: I’m sure Bach would prefer it to be played really well!’

The recording uses the 1955 Neue Bach-Ausgabe edition by Alfred Dürr, but Doyle made a number of minor tweaks which he sent to his singers via their iPads. ‘There are many places where you have to compare the early version with the later D major manuscript. I made a few changes that you would hardly notice, for example to the word underlay, and a couple of accidentals, but mostly I followed Dürr’s completion of the ‘Virga Jesse’ counterpoint [part of which is missing from the manuscript]. I like to think that what we’ve done is capture the spirit of the earlier version and do it as if I’d had the chance to talk to Bach and ask him, “Did you really mean this note here, or would you prefer it like this?” I suspect he may sometimes have said, “Yes, the later one is right, but I still quite like the first one.” That was my plan, and I don’t think there’s anything in this version that sounds like it’s lacking, or that we’re clunkily following the original for the sake of it.’

As he goes along, Doyle points out some of these places in his score, which I can see is plastered in coloured markings, post-its and other pieces of paper offering prompts, reminders and encouragements. One of the most unusual and emphatic looks suspiciously like the little diagram you see on a car gear knob: ‘That’s at the end of the “Suscepit Israel”, where you’ve had some wafting C major sounding like it’s heading towards F minor, but instead the “Sicut locutus est” starts up in stile antico polyphony in E flat major. It’s a massive gear-change, so this sign is to remind me of that, and that I need to take plenty of time here.’

It’s not hard to see why such reminders are required in a performance of the Magnificat; some movements are barely longer than a minute, and the changes of mood come thick and fast. Doyle says an important part of his preparation is to write out the text in full beforehand. ‘That’s my structure, like a screenplay, essentially. Then I look at what Bach has done with it, which makes you much more conscious of things like the layout of the verses, and which words he has chosen to repeat 17 times and which not at all. I find that sense of the bigger-scale topography comes in handy in a liturgical piece.’

But capturing the mood of a movement in seconds must also be a big challenge? ‘You’re right, you have to find the Affekt very quickly. But Bach knew what he was doing. Most of this music doesn’t even need a conductor, just a process by which the performers can establish a unified version of what they are trying to say. In the “Suscepit Israel”, for example, with those unison upper strings in slowly pulsing crotchets, all you need to decide is how long to make them. But they are there to support and sustain Israel and all Israel’s children, and that’s where the interpretation comes in. You need to be able to step back and see what the score says to you.’

I end by asking Doyle to pick some highlights. ‘So many!’ comes the reply. ‘There’s such ebullience in those opening bars: “bim-pam” from the strings, “dubba-dubba dubba-dubba” in the oboes, “dum-dum-dum dum-dum” from the brass. You’ve got these three things going on from the word go, and you can choose what you want to listen to. When the choir enters, it’s wonderful – they don’t start on the first beat of the bar, or on the up-beat, but just after the beat. There’s a wooden-legged joy to it all. Then there’s the build-up at the end of the “Fecit potentiam”: this is God in his wrath, so of course you have trumpets and drums, but also you have “dispersit” (“scattered”) going down through the parts and then this big chord on “superbos” (“the proud ones”) that really rips the music open. It’s Bach saying to us, “That means you, you’re the proud ones, it’s all of us.” It’s the kind of drama you get in Handel’s Dixit Dominus, and the performance really ought to make you feel uncomfortable here. Likewise in “Esurientes”, that last note shouldn’t sound in any way comic, just the cello, bassoon and organ placing it absolutely as one to represent the rich being sent “empty away”. These are the kinds of highlights that come from Bach’s genius in enabling us to bring the text to life.’