Chicago swung open its door, grinned, sat me down and handed me an ice-cool beer. That’s how it felt. After a hectic, kaleidoscopic week in New York City and a restful, uneventful twenty-four hours in Boston, the Illinois capital was a Goldilocks special: busy but friendly, impressive without threatening to overwhelm. I set down my suitcase in a tall brown hotel which was plain, gently shambolic, and just fine: situated in happy proximity to the vast Lake Michigan, the winding Chicago River, the lively North Michigan Avenue. Over the road appeared a dedicated popcorn restaurant: the smell of caramel oozed from its perforations. Further along, I encountered the best coffee I’d had in all of North America (a place called Intelligentsia, if you want to know) and a trio of men pouring saxophone sounds into the sun-pocked breeze. On another street, I descended into a gastronomic cornucopia: a two-floor market overflowing with fresh alluring treats and a vast library of liquor. A wall of beer captures my attention for about a half hour, every variation of ale, lager, stout, witbier, pilsner and porter you could dream of and ones you couldn’t, infused with things I’d heard of and things I hadn’t, offering themselves up by the endlessly mix-and-matchable half-dozen for less than a single Crownie will set you back at Tullamarine airport. Chicago, I whisper as I pry open the first deftly orchestrated IPA, you make a pretty fine first impression.

On the horizon to my left is the blurred blue surface of Lake Michigan – a lake by name and nature but an endless ocean to the naked eye. To my right are the bold edifices of Chicago city, from the ornate cathedral-like Chicago Tribune building, to the staunch prismatic geometry of Mies van der Rohe’s skyscrapers, to the tiered gleam of the Trump tower. But straight ahead is a park, sunken into a vast block, decked with seats and low walls, and adorned with a remarkable bandstand designed by Frank Gehry, whose silvery tubes and bent turrets twist dramatically above the treetops. This is Millenium Park, my destination for the evening, a place where every Monday bands and performers have been playing to eager listeners, at none of said listeners’ expense.

Tonight I’m drawn down by a band called Pillars and Tongues, who I’ve never listened to but have read about. They take to the rostrum with a curiosity-piquing array of tools: violins, hand-pumped harmoniums, percussion-laced drum kit and a smattering of rock and electronic staples. As we wade into their sonic pool, it becomes clear that their compositions are every bit as interesting: looping, rippling, droning folk-steeped explorations dappled with contemporary electronic beats and stealthy sojourns into pop-song lucidity. Among the hum and flutter of strings, the nostalgic bounce of chorus-tone almost-funk bass, the mystic wheeze of harmonium and the pagan throb of cyclic percussion, Pillar and Tongues’ most distinctive feature is their unabashed use of rich and mellifluous vocal harmony, a texture which sets them apart from various experimental contemporaries. The pristine vapour-cloud of their conjoined voices wouldn’t sound misplaced in a band like Fleet Foxes, but here – in the more avant-garde context of their instrumental wanderings – it’s particularly interesting, and forms a tactful counterpoint to their sporadic scuba-trips into noise, subsonic rumble and dissonance.

The amber sun sneaks out of sight as Pillars and Tongues wrap up, and following on are a band called The Both. It’s a duo – albeit augmented here with drums – comprising Aimee Mann (prolific soloist of ‘Magnolia’ soundtrack fame, formerly of ‘80s new wave band ‘Til Tuesday) and Ted Leo (of long-running indie outfit Ted Leo and the Pharmacists). Mann handles bass, Leo fields guitar and together they harmonize or alternate in the vocal department; their voices are both well-trained yet nonchalant and drawling, making for a nimble but pleasantly slack vibe all round. In contrast to Pillar and Tongues’ cinematic sprawl and immersive lack of banter or interruption, The Both put on a classic pop/rock show: a clearly delineated trajectory of capital-s Songs, with pauses and chatter in between. They start loud and adrenalized, ducking and weaving through robust riffs, radio-ready vocal hooks and specky-but-not-too-specky guitar solos, all of which ultimately serve a sense of rhythmic momentum and pop craftsmanship (the cheery ghost of the Beatles haunts even their most post-punky, gritty moments). They only released their first album in April this year, so their back catalogue barely suffices for a live set: in a more long-form performance like this, that means they need to call upon their separate oeuvres of both Mann and Leo. Luckily, doing so gives them a chance to flaunt their versatility: Mann performs one of her own low-key solo tunes (“Save Me”) on acoustic guitar, recalling the likes of Gillian Welch; Leo pulls a few tricks out of his sleeve too, boasting idiosyncrasies that might not have made their way into the Both’s middle ground. Indeed, there’s no attempt to pretend that the duo is a fully-formed, conceptually realized project: it feels more like two buddies working on tunes together and bringing their own musical lineage to the table, finding overlap in their respective sounds and forging a few really great rock songs in the process. Their debut single “Milwaulkee” (which describes, among other things, a weird undersized statue of the Fonze) hints at the pair’s dry sense of humour, which comes to the fore in their between-song conversation: if they get sick of playing tunes, the pair could have a healthy career in comedy ahead of them.

After a bunch more solid choruses, wild solos and neat arrangements the set reaches its finale, but the crowd are insatiable. The duo returns for a few final songs, including Mann’s earworm of an 80s hit “Voices Carry” which she wrote for ‘Til Tuesday. I walk away from the warm ambience of the park, down towards the river when yellow lights ripple in the black night-water. It was remarkable luck to stumble upon a double bill like tonight’s, for free, in public and on a Monday night. In a rare scenario, I now have two bands on my radar that I’ll probably continue to follow, by virtue of wandering to two live sets on a whim. For now, Chicago keeps kicking goals. I pop open some delicious Illinois brew and wander on into the evening.