This barn dance is a little sinister. The music is high-energy but it's potential energy, the quintet onstage not sharing in the often up-tempo nature of their music and the revellers, whilst happy, near-static as if something unspoken is afoot.

The hosts of this uneasy party are Johnny Flynn & the Sussex Wit, and the man on the microphone sounds both wary and wise beyond his twenty-something years, his music a mixture of thigh-slapping, hand-clapping country and lonely folk for the quieter moments, almost everything sorrow-dusted from the minor keys and the sweeping cello parts to the stark but uplifting lyrical composition. He's a narrator by nature, the songs as much about his characters as his own viewpoint, worldly tales spun of humble homeless types, of injuries both physical and emotional and of being happy with what you've got, each told like war stories around a campfire.

He's not in bad company tonight either, with Nic Dawson Kelly opening the show with a part-solo, part-band set, an old blues singer trapped in the body of a skinny white folk musician, his impassioned voice switching from throaty yells to a heavy quiver. An acquired taste he may be, but he's made to look positively normal by the debut showing of boy/girl duo Supertalented and their minute-long, cutesy anti-folk songs about not wanting to go to Brazil because it's too poor and not European, or perhaps how people without Firefox and googlemail are gay. Delivered with tongue firmly in cheek, the sheer nervousness of the performance can be charming but the air is mostly of disbelief, and no matter how much anyone wants this to be great, that doesn't mean it is.

So it's down to Transgressive's Mechanical Bride to wake The Luminaire up, a task at which they just about succeed. Leader Lauren Doss might be slight and shy - “the last time I tried to stand up and play in this venue, I ran crying from the stage”, she offers – but her voice is delectably soulful, and her three accomplices share the instrumental spoils, trading places at the keyboard, glockenspiel, tuba, euphonium, Theremin, accordion and whatever else is hidden away to form a sound entirely peaceful in nature. The softly-mounting slow-motion explosion of Rhianna cover (and recent single) 'Umbrella' is the first moment tonight where the crowd are united in appreciation, even if they might not yet be the finished article.

Meanwhile, Johnny Flynn and his Sussex Wit do resemble the real deal. The quintet are as tight as they need to be, Flynn's fresh vocals carrying the same genuine presence as on record and his handful of sad melodies accompanied by either rootin' and tootin', harmony-toting, full-on country jaunts (see forthcoming single 'Leftovers'), bop-along ditties with their country 'n' western chests puffed out in the chorus ('Cold Bread', 'Eyeless In Holloway'), or traditional folk ('The Wrote & the Writ'). The air it gives off is completely timeless – this could be from any era from the present day right back to the old scratchy roots records playing between acts – and the lack of communication between artist and audience only heightens the feeling that perhaps, just perhaps, Flynn isn't actually from these parts at all.

Eventually, it becomes consuming; this music which could by rights be greeted with hollering and stomping instead observed with respect. Songs and instruments come and go – Flynn himself switching between banjo, trumpet and violin when he doesn't have an electric guitar in hand – and whilst there's an argument to be had that this show might work a little better with a touch more movement in the livelier parts, their strength as a unit suggests that maybe we should be quiet and let them get on with being excellent instead.