The statistics are impressive. Seventeen CDs (one of which is given over to a conversation – entirely in German – between Martin Schmeding and Mirjam Wiesemann), with a total playing time only a trifle shy of 20 hours. The 172-page booklet, alternating between German and an idiomatic English translation, is thick with archive photographs of Reger with various friends and acquaintances. It includes an entertainingly informative 50-page commentary on the music by Schmeding himself which cleverly traces each of the works through a chronological sequence, allowing ample scope for biographical insight. There are generous details and fine colour photographs of each of the 11 organs used. The recordings were made in 12 sessions covering in total some 45 days between March 2014 and July 2016, and no fewer than 21 different registrants were brought in to help manage these historic organs.

But the most impressive statistic is the music itself: 221 individual pieces contained within 28 opus numbers and part four of the list of Works Without Opus Numbers compiled by the Max-Reger-Institut. This represents less than a quarter of Reger’s total output of 147 opus numbers and the eight-part WoO catalogue.

Amazingly, all these big numbers are handled by just two people. The entire Reger organ oeuvre is played by organist and Reger fanatic Martin Schmeding (who, if the double-page spread on pages 154 and 155 is anything to go by, models his physical appearance on Reger himself), while producer/engineer/editor/designer Ingo Schmidt-Lucas seems to have done just about everything else. He has not only produced first-class recordings of these various organs in vivid and real audio, but has handled what are, if the anecdotes in the booklet are anything to go by, some pretty awkward and unexpected obstacles during the sessions. Against this, the recently issued 16 disc Naxos set of Reger’s complete organ works was recorded over a period of some 20 years by 12 organists on seven organs.

Reger’s organ music comes in for a lot of stick, not least from organists themselves, and phrases like ‘turgid invention’, ‘dense chromaticism’ and ‘solid seriousness’ are frequently associated with it. Martin Schmeding does something pretty remarkable here. He makes Reger’s music not just utterly listenable to but hugely absorbing. Indeed, as well as bringing a brilliant technique and a searing musical mind to it, he adds a great deal of charm and, in places, humour. His playing simply oozes conviction, and on every one of these discs there are moments to savour. Where other organists find reams of dry fugues and complex wrappings around chorales little more than an excuse for technical display, Schmeding finds an opportunity for musical wit and rich organ colour. With his almost faultless delivery, this music unfolds with a tremendous sense of ease and naturalness.

I love the sprightliness he brings to the sixth of the Op 47 Trios (Vol 10) and the glorious sense of majesty he invokes in the great Fantasia on Wie schön leucht’t uns der Morgenstern (Vol 4). In the big works Schmeding is more than a match for anyone else, but it is in the smaller and overlooked pieces that his uniquely perceptive approach to Reger is best revealed. Of course, there are moments of dreariness in these which not even Schmeding’s enthusiastic advocacy can overcome. The tediously repetitive four-note theme of the Basso ostinato from the Second Suite (Vol 8) fully justifies the contemporary review quoted in the booklet-note, which described it as ‘having artistic struggle as its goal’. But there are plenty of hidden gems, notably the three-minute Altniederländisches Dankgebet (Vol 13) which was, according to Schmeding, ‘nothing more than a paid commission’. While this piece does not reveal great inventive powers on Reger’s behalf, Schmeding uses the relatively modest 1906 Sauer organ of Neuzelle Abbey to such good effect (with 24 speaking stops, the smallest of the organs used) one can only hope it satisfied the original commissioners. (We do not know who they were, nor what Reger’s fee was, although we read that he did write the dramatic one-minute Praeludium in C minor (Vol 13) in return for some ‘fine lemonade’.)

With a single exception, all the organs used were built during Reger’s own lifetime. The exception is the instrument in the St Nicholas Church in Leipzig – reputedly the largest organ in Saxony – which was originally built by Ladegast in 1862 before Wilhelm Sauer rebuilt it in 1902 03 (Vol 15). The largest organ of all is the massive 113-stop 1905 Sauer organ of Berlin Cathedral, used for a riveting performance of the rarely heard Sonata in F sharp minor (Vol 14). Only the somewhat cumbersome 1908 Sauer instrument of the Church of the Redeemer, Bad Homburg, sounds a little coarse around the edges in the four mighty Chorale Fantasias (Vols 4 and 5).

In every sense this a revelatory release, introducing some fabulous organs in vivid recorded sound, establishing Reger not just as a prolific composer but as an entertaining one too, and presenting an organist with real communicative instincts.