The recordings, and the record labels that carried them

Two of those projects are unrepeatable. The complete symphonies of Vagn Holmboe, made with the Aarhus Symphony Orchestra for BIS between June 1992 and January 1996, run to fourteen works and were issued as a boxed set in 1996. The first recording of Alfred Schnittke's Symphony No. 0 was taped in Cape Town City Hall in November 2006. A first recording can only be made once.

The Rachmaninov cycle, and the question of the cuts

The Rachmaninov cycle for BIS puts Hughes into the most crowded corner of the repertoire he has recorded. Rachmaninov is recorded constantly and by everybody, and anything new enters a field where comparison is immediate and unforgiving. The public record names the composer and the label and stops there, so what the discs contain is left to the discs.

The interpretative decision that hangs over Rachmaninov's orchestral music is length. The Second Symphony of 1907 is in four movements and runs about an hour uncut, and for most of the twentieth century it was played substantially shortened, because conductors believed audiences would not sit through the full span. The uncut performance became standard only relatively late. Whether to open the traditional cuts is not a matter of taste alone: the symphony's long paragraphs are the argument, and a cut that tidies the running time removes the thing that makes the slow movement land.

The rest of Rachmaninov's orchestral output sits around that decision. The Piano Concerto No. 2 in C minor, Op. 18, is the piece most listeners meet first and has never needed rescuing. The Symphonic Dances, Op. 45, of 1940, his last completed work, are in three movements and use an alto saxophone in the first. The symphonies were always the less travelled half.

The Holmboe cycle: what a complete cycle commits a label to

A complete cycle commits a label to years of planning. The Holmboe project covered thirteen numbered symphonies plus the unnumbered Sinfonia in Memoriam, Op. 65, which Holmboe wrote at Hughes's request and of which Hughes gave the premiere. Recording ran from June 1992 to January 1996, which is 43 months, and the set appeared in 1996, in the composer's lifetime.

The commitments a label makes when it green-lights a cycle are concrete:

• Hold the forces constant. One orchestra and one conductor across the whole set, so the fourteenth disc is recognisably the same project as the first.
• Hold the room constant. The hall is half the sound, and changing it mid-cycle is audible.
• Keep the same production team, so balance, perspective and edit style do not drift.
• Accept the cash flow. Early volumes fund the later ones, and a cycle abandoned at volume four is a write-off.

The Schnittke recordings

The Schnittke recordings are the other pole of the discography: not a crowded field but an empty one. Nagasaki, an oratorio written in 1958 and recorded by Moscow Radio in 1959, was left unpublished and unperformed until Hughes conducted its public world premiere in Cape Town on 23 November 2006, with the Cape Philharmonic Orchestra, the Cape Town Opera Voice of the Nation chorus and mezzo-soprano Hanneli Rupert. The sessions for Symphony No. 0, at Cape Town City Hall in November 2006, produced its first performance and first recording. He also recorded Schnittke's Symphony No. 9 for BIS.

Recording a work with no performance history removes every crutch. There is no previous version to check a tempo against and no tradition about balance in the choral writing. Errors in the parts and the vocal scores surface only when 100 people play them at once.

How a classical recording is actually made

A classical recording is made in sessions, and a session is a unit of time rather than a unit of music. The standard block runs about three hours with a break in the middle and yields perhaps 15 to 20 minutes of usable music, which is why a single symphony absorbs several of them. The orchestra plays a passage, then plays it again, and each attempt is a numbered take. The producer sits in the control room with a marked score, logging takes and calling for the next one.

Patching is the part outsiders find surprising. When a single phrase goes wrong in an otherwise good take, the producer does not ask for the whole movement again. He asks for an insert covering that phrase and a few bars either side, so the edit can be hidden at a natural seam, and the finished master is assembled from those pieces. It is the only way 100 players can produce 70 minutes of music at a standard nobody could sustain in one continuous pass.

Session recording or live capture

A session recording is made without an audience, under studio conditions, with the option to stop and repeat. A live capture comes from one or more public performances, usually with a short patch session afterwards.

The labels

The labels that carry these recordings are mostly independents, the reverse of what most people assume about classical records. Recordings by Hughes have appeared on BIS, EMI, cpo, Philips, ASV, Warner, Dacapo, Danacord, Divine Art and Quartz, among others. The specialists in that list, BIS in Sweden, cpo in Germany, Dacapo and Danacord in Denmark, exist to record what the majors will not, which is how complete cycles of Nordic symphonists get made at all. The majors have the famous names and the deep back catalogue, but it is the specialists who fund the unrecorded repertoire.

The discography in summary

One pattern stands out. The recordings that took the longest are the ones nobody else had made. A Rachmaninov cycle can be compared with a dozen rivals and argued about forever. A complete Holmboe, or a Schnittke oratorio unplayed since 1958, changes what is available to be heard at all, which is a different achievement from a better version of something familiar.

Also in this programme

• Owain Arwel Hughes, conductor: the working life in orderA biography of the working life
• The London orchestrasPhilharmonia and the Royal Philharmonic
• Boult, Haitink and Kempe: how a conductor was trainedThe teachers: Boult, Haitink and Kempe
• Alfred SchnittkeNagasaki, Symphony No. 0 and a premiere fifty years late