Marcus Eoin and Michael Sandison specialise in what you might call "inexact science". Operating since at least 1995 (in keeping with their aesthetic, the group are artfully vague about their early history) as Boards Of Canada, the Scottish band have challenged many of the traditional reference points of electronic music. Theirs aren't albums that fetishise efficiency and technology, hedonism or travel, and they don't seem to have much interest in emulating or soundtracking that electronica fallback position: the busy urban experience.
Instead, much as 1960s rock groups were said to be "getting their heads together in the country", in their music, the pair (who take their name from the Canadian National Film Board, makers of, among other things, nature documentaries) draw inspiration from the currents of the natural world: sunsets, campfires, beaches, birds of prey. All round, the music of Boards of Canada speaks more about the organic and the fallible than it does about the certainties of the computer. In describing it, the band have occasionally referenced psychedelic drugs.
So, at any rate, it has delightfully been for the three albums (alongside great stand-alone EPs) that the pair have made for Warp records since 1998. The best music by Boards of Canada, such as, say, Kid for Today from their In a Beautiful Place Out in the Country EP of 2000, Alpha and Omega from their second album Geogaddi (2002) or the lovely Jacquard Causeway here, is propelled by hip-hop beats, but builds on them with melancholic chords and wonderfully eerie top-line melodies. These are then treated with delay and echo to a mesmerising effect. Voices periodically emerge from amid radio static. It's like hearing a tune actively being passed from generation to generation, gathering dust, subject to decay but retaining its essence.
This is obviously minutely organised stuff, but the cumulative effect is probably more folkloric, even mystic. The band themselves, while not completely unavailable (they even occasionally give interviews) aren't afraid of encouraging this.
They have built their own mythology based around shapes (they derive from a Pentland Hills art collective called Hexagon Sun, now the name of their studio), and significant numbers (70, a "weird number", is one of them). Their second album Geogaddi, rightly thought to be a far darker record than their 1998 debut Music Has the Right to Children, (in which the gay laughter of children was a feature of the soundworld) is 66 minutes and six seconds long. Like, 666, right?
The band has a devoted fan community that dissects and anatomises just this kind of thing. A post from a few weeks ago speculates of Kid For Today: "It has been suggested that the percussive clicking sound heard throughout is the noise of a slide projector …" Another notes that the combined file size of Geogaddi is 666MB. In fact, so filled with mysteries and unanswered questions is the band's music, Boards of Canada fans have begun their own investigations, a happy and supremely creative fog of myth and supposition that has provided the same kind of diverting and confounding relationship to the Boards Of Canada musical experience that a selection of good DVD extras might have to a feature film.
With their new album, the excellent Tomorrow's Harvest, the band and its agents have actively sought to harness and collude in this kind of forensic interest in their work. On Record Store Day (April 20th 2013, an occasion when music artists gather together to celebrate the vinyl record and the high street outlets that sell it), the band dropped copies of a record into select stores. The audio of the record contained nothing but a sequence of numbers and a clue to their place in a sequence. The fortunate guy who bought a disc in New York's Other Music outlet hopes to fund his college education with the proceeds of an eBay resale. The six weeks or so since has, for Boards of Canada fans and amateur sleuths (the two are often indistinguishable), proved enormously entertaining, an unfolding series of clues uncovering a website for a mysterious front company (www.cosecha-transmisiones.com) into which the sequence of numbers might find a home.
The most dramatic moment in the campaign was probably when someone on a Boards of Canada messageboard noticed that a banner advert had changed location and appearance on the site. They opened it in an editor and found a new clue, placed within the code for the banner. The "Cosecha" website ultimately revealed the album's title and release date.
For those of us in the fortunate position to be able to request the album through a representative from the record company, the situation is pretty awe-inspiring. Rather than attempting to market to a new audience, the events of the last few weeks imply that the only people who deserve to hear the first Boards of Canada album for eight years are those people who have such empathy with the artist that they will actively interpret the minute barometric changes that let you know it is on the way.
Nothing, it turns out, could be further from the truth. Certainly, the tone of Tomorrow's Harvest is minutely controlled, and features some of the band's classic strategies (an implied ecological agenda; an involving use of melancholic chording and hip-hop drums). But whereas Boards of Canada's music has often drawn strength from appearing ghostly, even accidental, this is an album that feels broadcast, not merely overheard. It feels designed to be engaging, as if (to pick up the film analogy), having put together a trailer that promised so much, it is particularly vital that the main feature should not be disappointing.
Assuredly, it is not. Unusually for Boards of Canada, this is an album where you cannot only speak about compelling mood and mind-expanding atmospheres, but also about influences and standout tracks. The excellent Reach for the Dead is the first such: a widescreen piece that opens with what may be ominous, distant distorted guitar feedback, but which quickly evolves into a beatific drone reminiscent of the 1970s Kosmische of Klaus Schulze. A driving pulse propels the song towards its close in a joyous fanfare. It's evocative of new dawns, scientific breakthroughs: men with beards and white coats, cells dividing under a microscope, man and machine, working in harmony. That, however, may be a misleading hope.
A while later, we find the longest track, Jacquard Causeway which (like the nuclear winter techno of Cold Earth) calls to mind Kraftwerk's Radio-activity album, in which Geiger counter crackles, decaying melodies and radio static were juxtaposed in a supremely artful comment on global communities: easily connected by radio waves but just as easily destroyed by radiation. Given this reference, it may be helpful to note that Tomorrow's Harvest, it turns out, is also the name of an online retailer of long-life foods for survivalists.
In the context of great tunes like this, the likes of Telepath (in which numbers are solemnly intoned) or Collapse (in which human voices are malevolently submerged) can feel a little like scare tactics. Really, the group have no need of them, such is their command of ambiguous mood. The punning Split Your Infinities has its shadows lifted by insistent hi-hat rhythm, while the following Uritual, with its electronic cicada and Morse pulses is a far darker transmission. Sick Times, at about the halfway point, fills the sound picture with gloomy synthesiser, but soon crests the wave of an insistent and joyous dance beat: it could conceivably be early 1990s work by Orbital, then pioneers in rurally minded techno.
Having managed the mood (loosely: questing, into a thrilling but uncertain future) impressively, it is in the final four tracks that Boards of Canada show their mastery of an engrossing musical drama.
A suite that begins quietly with Sundown, it peaks with the driving New Seeds (by far the album's most insistent track, and soon no doubt to be a fixture of TV continuity). The closing Come to Dust (stirringly tuneful like Roxy Music's Avalon) and Semena Mertvykh (which a brief investigation suggests may mean something like Dead Knowledge) provide an elegiac point of departure.
An assumption of graphology, by which handwriting is analysed, is that those who form letters with no ambiguity, whose writing is apparently easiest to read, have the most to hide. Those whose script at first appears filled with problems of interpretation, ironically, are in fact the very people who are inviting you in.
Self-evidently, Boards of Canada are the warmest examples of that second case, enticing us with clues to their apparently inscrutable world, but revealing a place of beauty, fragility and great adventure once inside.
It's an engrossing place. But as to what it all actually means? The definitive answer will hopefully elude us for a while yet.
John Robinson is associate editor of Uncut and the Guardian Guide's rock critic. He lives in London.