Porto, Portugal: Day 2 at NOS Primavera Sound and we’re back with a jampacked day of acts from across the world. Friday has a more distinctive rocky and indie pop feel than Saturday, with an ample range of post rock, experimental and noise for the thousands of festival goers.

The variety brings die hard fans and curious music sightseers without prejudice along to all four stages. Starting with American indie rock band Whitney, it’s a soulful sound reminisque of the 90s and full of freeing guitar, keys and trumpet tones on top of a warming and wandering bass line. And wherever festival goers were in the venue, they couldn’t fail to hear Missouri singer song writer Angel Olsen and her band, indie with touches of alt-country rising across the grounds.

A fantastically bizarre twist come with harshly abrasive yet completely addictive East Midlands ‘minimalist punk-hop’ duo Sleaford Mods, comprising of Jason Williamson on half-rant half-rap vocals and Andrew Fearn on beats (Fearn’s live performance amounts to pressing a button and doing a dance with a beer can in one hand). I can’t be sure that the Portuguese majority would have fully understood lyrics such as ‘The angel of the midlands has flown away / Probably south / You can’t blame her / When the future is a flag pissed on / And a king-sized bag of Quavers’, along with references to Coronation Street’s Ena Sharples, but they certainly did a great job dancing along.

Then came the most difficult choice of the day. Three acts had been scheduled alongside each other: the mighty experimental noise collation Swans, led by Michael Gira; the haunting and emerging singer-songwriter Julien Baker; and (they need no introduction) Bon Iver. As a result, the three acts enjoyed entirely different audiences.

Bon Iver was packed from stage to the crest of the hill. A mixture of die hard fans mixed with chattering teenagers and young adults led to an odd audience vibe, but Bon Iver pulled out all the stops on a visual and auditory journey through their new album release, finishing their performance on their old favourites.

Swans and Julien Baker coped more than adequately with the demands of their slot next to the main Saturday headliner. Julien Baker was a small yet mighty performer on the gulf of the stage, wielding her guitar and a loop pedal. Any show performer pretence is left at the door, and she’s humble at her smaller yet one hundred percent dedicated audience. ‘You’ve helped me change the worst things in my life into something positive and redeeming, and that’s given me a great gift,’ she says, referring to the runaway success of her first album.

It goes without saying that Swans ignored any set length constraints and played a good hour over their supposed finishing time. The band is playing its final shows in its current incarnation, and they will be very sorely missed. Michael Gira plays the role of singer, guitarist, conductor and magician of the stage amongst a whole host of talented and varied musicians. He regards the audience and performer with the same stern and commanding gaze, rotating slowly as their experimental noise roars from the speakers. One moment, he only needs an irritated flick of the hand to bring the bassist or the drummer higher; next moment, he’s rocking back and forth across the stage almost wrenching the music out of his band members. If Gira could play ten instruments at once, he would no doubt make a mighty fine job of it.

The evening doesn’t whittle out there. Grime artist Skepta is next on stage playing mega hit Shut Down followed by  notorious psychedelic rock band King Gizzard and the Lizard Wizard, complete with characteristic guitar freak outs. The energy just rockets higher and higher. It’s 2 AM by this point and the crowd is beer fuelled and blurry eyed, but still throwing themselves head over heels into mosh pits and over the barriers with furious intensity. By the time the night ends at sunrise, it’s a relief that each day only begins at 5 PM, but day 3 looks set to bring just as much passion, diversity and exuberance to the heart of Porto.