There was a time - a decade or so ago - when mention of the term 'bluegrass' would either draw a blank or elicit a slight curl of the lip.
Then a cultural shift - caused, in part, by the runaway popularity of the 'grass heavy 'O Brother Where Art Thou?' soundtrack and the global success of Alison Krauss's sweetly palatable sound - brought bluegrass towards the mainstream and away from its image problem.
On Saturday night (30th January), the Southern Tenant Folk Union showed the audience at the Villa Marina's Promenade Suite both how thrilling traditional musicianship can be and how effortlessly bluegrass can be blended with other genres - folk, roots, americana - to make a potent, timeless sound.
There were two local support sets before the Edinburgh-based group took to the stage: in lesser hands, this might have an embarrassment of riches but singer-songwriter Anna Goldsmith showed once more why she adds to her fanbase every time she plays live.
Anna was followed by Tramwreck, a newly-minted guitar trio put together especially for the occasion. The down-home strum and stomp served up by Nick Barlow, Johnny Galbraith and Andy North provided a fitting warm-up for the performance which followed.
The Southern Tenant Folk Union were formed in 2006 but sound as though they could have sprung to life any time in the last few centuries. This is a testament to the musical chemistry of the band rather than their attitude to the genres they handle, which is one of respect rather than reverence.
Laments, love songs, prayers and protests were injected with equal parts vigour and sensitivity; grounded by rhythmic foot-stamping (no drums required) and set soaring by gorgeous harmonies.
The 'STFU' gave a masterclass in ensemble, ego-free playing, with each member tempering their individual flair to create a powerful whole - a folk union indeed.
Chiming in with affable frontman Pat McGarvey's 5-string banjo were Chris Purcell and Jed Milroy on guitar and vocal duties, Silas Child on upright bass, fiddler Roddy Neilson (the former Peatbog Faerie giving one of his last performances with the band) and Adam Bulley, who unleashed perhaps the only mandolin solo the Villa Marina will see this year.
At the close of two generous sets, the band shook up the encore tradition by moving into the thick of the audience and playing two numbers unplugged or, as McGarvey put it, "as the music was intended to be heard". If anything, their sound gained in stature, and it provided a beautiful final movement to the night.