Living in the city is alternately an experience of exhilarating interconnectedness and one of unbearable loneliness. On the good days, you share a sympathetic smile with your fellow commuters on a packed Tube train, you trade easy banter with the cashier at the Sainsbury’s checkout, and you feed off the buzz of the crowd as you head out for a night in Shoreditch. On the bad days, you jostle the swarm of straphangers for a seat or a spot next to a pole, the cashier hands over your bags and change without a word, and people who bump into you on the street don’t even glance back to make sure you’re okay.

City Songs, with music by Latvian composer Ēriks Ešenvalds and words by Australian poet Emma Jones, is a celebration of the joys of city living on one of the good days. This hour-long work, commissioned for the Voices Now choral and vocal music festival, premièred on Sunday evening as the closing performance of this four-day series at the Roundhouse, with massed choirs and the City of London Sinfonia conducted by Stephen Layton. In the very loose narrative of the piece, a doe-eyed traveller – performed by British singer-songwriter and multi-instrumentalist Imogen Heap – enters the city looking for her childhood home, her haunting recitative set against an urban soundscape of traffic noises, church bells, and chirping birds. Along the way, she encounters different groups of people, including workers, commuters, pedestrians, buskers, and even a parade.

This storyline is, of course, mostly just a pretext for showcasing the abilities of the six choirs, which are drawn not only from around London but also the south of England and Northern Ireland, and together reflect a wide range of musical traditions. Ešenvalds first imagines the choirs as the music on the traveller’s radio, enveloping the audience in the richness of over 200 voices by placing the choirs all around the room. He squeezes every last drop of cuteness of out St Mary’s School Choir in his songs of daybreak and nightfall, complementing their youthful voices with egg shakers, pizzicato strings, and charmingly off-pitch child soloists. He exploits the Roundhouse Choir’s speciality in musics of the African diaspora, using the choir to portray city workers as labourers singing African American-inspired work songs, complete with percussive sounds created using only their own bodies. If the musical choices at times seemed somewhat obvious, they were executed with such exuberance and energy that you were willing to extend a bit of grace.

Besides, who hasn’t, on those good days, imagined that the city is singing out with all their joys and sorrows? Who hasn’t considered that the chugging of the wheels on the Tube is really the steady chant of ageing trains that have seen 150 years of London history, singing “we remember, we remember”? Who hasn’t wished, when they are lost in the maze of London’s city streets, that they could know, with the absolute clarity that can only be provided by the majestic voices of a four-part choir and the glorious weight of a full string section, which way to turn? (“Turn left!!!”)

Even the less successful elements managed (although, perhaps, inadvertently) to capture the sense of living in the city. The soprano saxophone was a pervasive presence throughout the piece and could be counted on to enter at the moment of emotional climax in each song, doubling the melody at the octave. It was as reliable as that saxophone busker in the Underground who you just know is going to be playing the same eight bars of “Careless Whisper” each time you pass through the station. Amidst the tumult and anxieties of urban life, there’s something vaguely comforting about that.

When I stepped out of the Roundhouse after the concert, Camden was still abuzz with people milling about the market and wandering around by the lock. Cyclists rang their bells, buses whinged down the street, and teenagers shrieked with laughter as they horsed around on the sidewalk. On any other day, it have sounded like a typical urban soundscape. But this was a good day, and to me, it sounded like a song.