Jessica Pratt @ The Blue Arrow, Glasgow, 25 Mar

By the dreamlike synchronicity of act and venue, it was easy enough to conjure a mental image of tonight’s show. Jessica Pratt, a San Franciscan singer-songwriter in the loosest sense, preaching to the choir of seated Bohemians in black. Having only recently widened its musical net, Glasgow’s Blue Arrow is a basement venue usually trading in jazz acts, with an interior of tastefully lit exposed brickwork and tables. This postcard fantasy of the 20th century is, no doubt, the venue’s major selling point, and one befitting of Pratt’s gently free-wheeling authority.

The reality is dramatically different, and seems like the product of an organisational miscalculation ("we’ve sold quite a lot of tickets tonight", gasps an exasperated staff member). Here we are, the majority standing before a stage well below eye level, scowling at the lucky few who had the foresight to turn up two hours early and nab a table. Storming the gangway, we struggle over each other to get a peek of the woman herself, settling for a mere glint of her golden hair.

The shroud of mystery that surrounds Pratt is inviting of this kind of huddled reverence, this kind of exclusivity. Wrong Hand sows seeds that luxuriate into Greycedes, the sweeping nylon strings of her guitar sounding like the bare bones of a great, romantic lounge pop number. Her horizontal chanteuse style becomes more pronounced, as she moves gradually into a set which flexes the strong silence of her latest album Quiet Signs.

The Bacharach brass’n’strings of early Dionne Warwick records wouldn’t go amiss on recent singles Poly Blue or This Time Around (and her performance’s keyboard accompaniment does a just job of invoking early 60s pop). But there’s part of Pratt’s magic: her spectacular feats of melody, lovingly rendered tonight with astounding accuracy, become pronounced by the scarcity of the instruments surrounding her. Just like its ear-shattering antithesis, it’s an operation performing music as quiet as this. This is made apparent when the sound of Pratt’s microphone on the mounting two-parter Opening Night and As the World Turns threatens to peak at one point or another, promptly reined in by our steadfast sound guy.

Three albums into her quietly influential career, the curiosity of Pratt’s lyrics stems from their confessional singer-songwriter tone, concealed by tape hiss and her particular singing style: largely pursed and elven, rounded where you don’t expect. Each new release hosts scenarios viewed through a pinhole, as if bearing direct witness were tantamount to staring at the sun. You might believe that the gait-weakening loveliness of Here My Love would become clearer in this live setting, but you’d be mistaken for thinking that having Pratt before you in the flesh would ever remove these pesky mediators.

Nearing the end of her set with On Your Own Love Again number Moon Dude, it’s clear that the enduring mystery of Jessica Pratt remains intact. But this singer – acid folk’s progeny with the city-slicker charm of Joni Mitchell – in this place? Nobody here tonight can say we haven’t been witness to something altogether quite special (except perhaps those individuals right at the back).