Bowed guitar to the fore, Jónsi Birgisson is one of the lodestones of 21st-century art rock. With Sigur Rós becalmed again (their last album was in 2013), and his other projects – Riceboy Sleeps and Jónsi solo – on mute, the Icelandic musician has corralled some previously unreleased electronic solo pieces under the name Frakkur. Some of these are loose on the internet in grainier form; a handful came out in a very short vinyl run last Christmas.

Dating from the early 2000s, these often engaging tracks take the form of amorphous ambient glides and playful digital sketches, each album corresponding to a different set-up of gear, locale, time and theme. The earliest tracks – SFTLB 1-9 – riff hard on innocence, while TB 1-8 find Jónsi sampling junk-shop toys into clubbier fare before a sonorous unease takes hold.

There is common ground with Sigur Rós – TB1, for instance, sounds like someone popping an Alka Seltzer while one of their records skips on a turntable – but these more minimal, often joyous outings benefit from a lack of bombast that characterises Sigur Rós and Jónsi’s solo album, Go (2010).