“How could I have known?” singer Alejandra Deheza swoons in the first line of ‘Ablaze’, the album’s stomping synthpop opener. Well, how could she?

The subtext is inescapable. SVIIB, the fourth and likely final album from the indie-shoegaze synthpop group School of Seven Bells, is the first released in four years after producer (and Deheza’s lover) Benjamin Curtis died in December 2013 from lymphoma aged only 35. Deheza, as the sole remaining band member, finished the record alone, a tribute to her former musical, platonic and romantic partner and the band’s fans, calling it “a love letter from start to finish”.

All but one of these tracks were produced and recorded by Deheza and Curtis together in 2012 before his untimely diagnosis. The dramatic irony that results is striking, infusing the record with double meaning and adding depth to what at first blush comes across simply as well-crafted pop. Throwaway lyrics become powerful statements all the more effective for their simplicity, as when a quick line affirming mutual respect in a relationship in the exhilarating On My Heart over uplifting synths and an unstoppable beat takes a tragic edge in the context of Curtis’s death (“There was a you before me, there was a me before you, and that’s the way it goes”). The effect is all the stronger for the tenderly optimistic mood of the track (and the album as a whole), as if Deheza is ignorant of and reflective about loss in equal measure, with sorrow and defiance playing off each other to weave a vibrant, doggedly human bittersweet texture as her vocals soar with lyrics like “With me your love’s safe”. Most tracks, on the surface, are an ode or an elegy; the mixture of layers of interpretation means they are often both simultaneously.

On past releases, School of Seven Bells could be rightly accused of long, borderline abstruse lyrical flushes. Here, their songwriting technique reaches its apogee, with evocative metaphorical details sitting alongside piercingly direct emotional sentiments (“Until I felt your hands on my skin, I felt nothing”). Deheza frequently evokes the air, the sky and the stars, using them as a springboard for her memories of her lover (“Do you remember when, in the morning hours, we would watch the stars play their song?”) and for digressions into fantasy (“Tonight I’m feeling the moon come through, stars sway under my feet, the lights all around me glow, and music takes me”). We share the sentiment in the opening line of Signals: Curtis is absent, yet we feel him pervasively close throughout, both emotionally and more literally, as album producer. All the while the synths continue their fierce pace, barely giving us time to digest the rich evocation of human feeling throughout. The musical and emotional parallels with CHVRCHES’s recent Every Open Eye are significant: if you loved that, you’ll likely love this.

As the band mourns the loss of one of its members, so too, particularly in the album’s first half, do the songs draw firm musical inspiration from the past – the throbbing, repetition-driven structures and lyrics of 1980s synthpop and soaring New Wave ambiance make for near-perfect retro tracks. That sheen is sacrificed for songs like Signals and Elias, where indie-pop experimentation and layered effects on Deheza’s vocals – a return to the band’s core sound – are less rewarding for sometimes lacking immediate hooks and masking the powerful lyrics lurking underneath. But Confusion packs the biggest emotional punch, the only track on the final cut written and recorded after Curtis’s diagnosis. Deheza’s exhaustion over languid, ethereal synths is real and raw, and in the right mood the song is devastating. “Confusion weighs heavy, and I understand nothing of these changes,” she laments, the album’s only explicit, direct acknowledgement of loss and pain.

That is far from setting the overall tone. Anthemic closer This Is Our Time encapsulates the broader optimism and vitality amidst mourning on these tracks: “Our time is indestructible”, “We own the night, we escape tonight to the haze of the bright lights”. The result is a moving and occasionally thrilling album that goes beyond a tribute to one man to make a broader, bolder statement about love, loss and life.