Fans of Iceland's greatest post-rock outfit haven't had the easiest of times. 2010 saw the near disintegration of Sigur Rós as lead singer Jón Þór Birgisson embarked on his own very successful solo project as Jónsi, and other members took time off to be parents and immerse themselves in life away from the road.

The band finally broke the silence with last year's Valtari, a sign that their 'indefinite hiatus' had indeed finished. 'We are almost finished working on the new album,' says Georg 'Goggi' Holm, bass player and founding member.

'In fact, we've actually spent most of the last year working on it. This album is quite different to anything we have ever done. It is hard to put the finger exactly on what it is but it is definitely different. Maybe it is a little more aggressive - in a good way,' he laughs.

The forthcoming, as yet untitled, record has been borne amidst a period of cataclysmic change for the outfit.

Last November the group confirmed long-time member Kjartan Sveinsson was no longer a part of Sigur Rós. The multi-instrumentalist joined the group in 2001; his keyboard and guitar work quickly became an important element in the band's signature ambient soundscapes.

Rather than mourn the loss of their friend and contributor, Sveinsson's departure proved a catalyst for rejuvenation within the remaining trio. 'The three of us haven't been this excited about new material in quite a while,' says Goggi. 'Personally, I haven't been looking forward to getting something out as much since we released [their second album, from 1999] Ágætis byrjun.'

The change may prove to be more than one of personnel, with Goggi hinting at a shift in musical direction.

'There are elements of the new record that are perhaps more evidently electronic than before,' he reveals.

'We have always used electronic equipment, especially in the studio for editing and experimenting, but this is perhaps one stage further.'

Fans of the classic Sigur Rós sound should not despair, however. While the gig will showcase the new record, it should also please devotées of their older material.

In preparation, the trio have bolstered their live set-up – not quite to the grandiose extremes of their recent show-stealing performance at Iceland’s Airwaves festival, where they played behind a giant white screen, backed by a classical orchestra. This Scottish visit will include the addition of two touring members, one of whom, Kjartan Holm, Goggi's younger brother, is a member of lauded Icelandic post-rock group For a Minor Reflection.

'We realised we needed someone to play the piano and the synths so we decided to bring in two people for the tour', Goggi continues.

'There is definitely something different to how the tracks are performed live now, especially the older songs. The sound seems a lot fuller and richer. That's really important to us because it gives room to experiment.'

Although the Glasgow set will include cuts from the forthcoming release, wranglings with their record label and their intensive recording approach means the album will be held back for a few months yet.

'We had a release date in mind but it had to be delayed,' admits Goggi. 'We want it out as soon as possible and definitely this year - probably summer.'

Sigur Ros play the SECC, Glasgow, Sat 2 Mar, with support from Blanck Mass.