For 30 years African Head Charge have been ploughing their unique sonic furrow, wandering hazy-dazed around the outer borders of experimental dub and super-mellow sounds. When they first appeared in 1981 on Adrian Sherwood's groundbreaking On-U Sound label there was no equivalent band to compare them to, except some of Brian Eno's global magpie studio excursions, notably My Life in the Bush of Ghosts with David Byrne which provided them with a sonic template.

Without intending to, Fleet Foxes set a benchmark with their debut album in 2008. One that resonated. So much so that the release of their second album, Helplessness Blues, is accompanied by sell-out shows at top-drawer venues. The love of their sensitively delivered, beautifully crafted and emotive folk rock is clear. But anyone expecting a rerun of the debut on Helplessness Blues is in for a surprise. What’s known and loved is here. There’re also more than a few left turns.

Sometimes it seems as though every bit of music from the past has been disinterred, no matter how obscure or outré it is. But, of course, surprises keep on coming and the Psychedelic Pernambuco compilation is a reminder that great stuff still lurks out there. Collecting material recorded for the Brazilian independent Rozeblit label, Psychedelic Pernambuco roams through weird folk, post-Tropicália strangeness, fractured instrumentals and more.

There's something about this album that feels as if it's already existed for a long time. Full of post-apocalyptic images of smoke, dust, decay and weakness, and themes of struggling individuals and implacable political forces, it thematically fits with the works of a long line of acts who positioned themselves against the fear of nuclear armageddon and the seemingly immovable Conservative government in the 1980s. Its mix of Caribbean-influenced soundsystem culture and dub poetry with an edgy alternative experimentalism, too, harks back to the post-punk genre collision of Dennis Bovell, On-U Sound, Renegade Soundwave and the like, 25 or more years ago.

The music of Hype Williams is the definition of an acquired taste. It sounds ramshackle, thrown together, deliberately awkward – either deeply contrarian or the work of very, very messed-up people just playing around with archaic home recording equipment. But immersion in it reveals all kinds of layers of strangeness, and particularly a rich and emotionally resonant sense of melody that weaves through all the clashing rhythms and crackly recordings. Even the arrangements, it becomes apparent, are not random, but show real complexity – although what is deliberate and what not is hard to pick apart. It slowly becomes apparent why a label as respected and aesthetically rigorous as Hyperdub might have picked them up as they have recently.

Drummers that sing lead are rare. Ones that sing while pounding away like Keith Moon are even rarer. Denmark’s Treefight for Sunlight are a talented lot, a four-piece who all sing, with three taking the lead. These are the vocals that drive the band and their melodies. Chuck in a wodge of psychedelic nous and you have an art-pop combo that can raise smiles and even the odd scream in hyper-cool Shoreditch.

Often at gigs by bands of a certain vintage, the fans can look like they're on a special awayday: like they've dug their T-shirts out of the back of the drawer and geared themselves up for one last canter round the paddock. Not so for Killing Joke. At the Royal Festival Hall last night, a very large section of the crowd had the look of still actively living very rock'n'roll lives, and of having done so for at least the last 30 years. “How many times have you seen them?” asked a shaven-headed gent in the seat next to me. “This'll be my 46th Joke gig,” he continued with obvious pride.

The Sónar festival occupies a very special place in the New Music calendar – and is this year expanding outwards temporally and geographically, with new franchises in Tokyo and A Coruña, Galicia. Now into its 17th year, the parent festival in Barcelona serves as a vital meeting point for those of all stripes who refuse to acknowledge the polarisation of avant-garde and populism, or of club culture and the mainstream music industry. With 10 or more main stages and untold off-piste club events around the city, it would be impossible to condense even a single day and night of Sónar Barcelona into a standard gig-venue show, but that's what A Taste of Sónar tried to do last night.

One of the great adventures of the 20th century is the story of LSD. A warped, unlikely slice of history not taught in schools, it has flavoured many aspects of life to this day. The countercultural explosion of the Sixties influenced the broader Western world - art, music, politics, religion, social issues and much more - and at its vanguard were key figures who believed that enlightenment might be found through the use of psychedelic drugs. These utopian mavericks were from all sorts of different backgrounds and they wanted nothing less than to turn society completely on its head, to change its value system.

I have thus far been a bit wary of the Janelle Monáe hype. It's only natural: when an attractive young performer is taken under the wing of megastars like Outkast and P Diddy, and drenched with media acclaim that pronounces them an artist on the level of Prince, all on the basis of a few download tracks and one album, one bristles. And when that album is heavily conceptualised and crisply produced but more full of overt retro references than it is instant tunes, the suspicion only grows. Live reviews, meanwhile, suggested that there might be something more stage school than old school about her soul stylings. I really didn't have many expectations for last night's show.