Imbogodom is the name of the collaborative project between Alexander Tucker and Daniel Beban, two musicians working in similar fields, but based at either end of the planet – Tucker in London and Beban in Wellington, New Zealand. It is an odd name for a band, suggesting a prog rock/ fantasy element, which is perhaps off-putting for some, but at the heart of their collaboration is a love of music concrete, the BBC Radiophonic Workshop and a keenness to experiment with found sounds and analogue equipment.

This is their second album and it carries on from where their debut The Metallic Year left off; the pair bonded over their interest in music and begun to record together whilst Daniel was working in London. Most of their debut album, and a fair chunk of this follow-up, was recorded using analogue tape machines and mixing desks during the small hours of the morning in Bush House, the soon to be decommissioned home of the BBC World Service. In fact the very first sound on the record is a single bong of Big Ben, a sound immediately associated with that station. So begins ‘Borogmog's Clock’, a piece built around ticking sounds. It is multi-layered but shifting and unsettling, it never establishes a regular rhythm, but instead creates an eerie, sinister mood which continues and develops over the course of the album.

And They Turned Not When They Went does differ from their debut though, as this isn't just an experiment in sound art, there are vocal pieces and some fairly conventional song craft as well. Overall it is more song-based and it manages to be more accessible whilst still retaining the weird and unsettling core at the heart of The Metallic Year.

By the second track 'Slate Grey Light', Tucker's distinctive vocal appears, familiar to some from his fine solo albums (Old Fog, Dorwytch, Furrowed Brow), but it's tracked along with Beban's to create a phasing, trippy effect, and the backtracking just adds to the overall feel of something pleasantly unusual. Two short experimental pieces follow – ‘Etchum Buoy’ has a voice which is so slowed down it doesn't sound human, and ‘Window Faces’ is another unsettling piece built around strange drum patterns.

‘Heir Looms’ is another hauntingly melodic song that could easily have fitted on Tucker's excellent 2011 release Dorwytch but has an extended coda full of echo and reverb and pitch shifting. For me it's the highlight of this set because it combines a memorable song somehow honed from ancient melodies with an eerie 'music concrete' backing track which gels beautifully.

‘Welcome Away’ begins with a phone call, a puzzled sounding Beban answers, distracted and surrounded by echo. It turns into a collection of bleeps and sound effects and is genuinely unnerving. Whilst ‘Red Brick Roundhouse’ is a pleasant drone with dominant cello and another floating baritone vocal, ‘The Passing Presence’ is as ghostly as the title suggests; high piano notes, creaking strings and percussion and decaying tape loops make an interesting collage. Similarly ‘I Am Here, I Am Gone’ returns to the abnormally low voice effects, tape loops with Tucker's conventional vocal lost in the background, intoning a distant melody. As well as using Bush House, some of this album was recorded in various old buildings at Dungeness, using the natural ambience of such buildings to add something to their sound work.

On closing track ‘Pillars of Ash’ both voices work together, but again this is a curious arrhythmic piece, shifting time signatures whilst floating ambiently as well.

This could be the soundtrack to an imagined horror film, but it would be one of those set in the countryside with a washed-out 1970s vibe, where there are no monsters, just sinister goings-on and familiar objects become eerie in a different light. This is a sinister, challenging listen, but one that stretches the boundaries of post-rock or psych-folk. However you wish to label it, these guys have taken that kind of music somewhere else and are moulding it into strange new shapes.