Founded in the early 1950s, discovered by the record industry in the mid-70s, touring world-music circuits since the late 80s, these 22 women and two plucky men produce a resonance every bit as awesome as Kelvingrove's great echoey vaults. Under the fierce precision of conductor Dora Hristova the singers have their routine down pat, reconfiguring between numbers like a team of elaborately costumed synchronised swimmers.
They've performed their greatest hits hundreds of times, of course, and the edges are by now glossy-smooth. The indelible magic comes down to a few key factors: the strange beauty of Bulgaria's folk songs; the off-kilter rhythms that set your feet tapping to time signatures you could never count; the brazen harmonic arrangements – barbershop to stabbing dissonance, meandering incantations to meshes of microtonal white noise; the range of vocal colour in everything from nasal duos to earthy 22-part ensemble. And all of it is delivered with airtight precision.
There was no explanation of what the lyrics are about or (my particular beef) who wrote the stunning harmonisations, so the choir keeps its mysteries fresh. But who really cares; to hear them sing is utterly transporting.