To me the defining sound of Spirogira is the contrast in vocals between Martin Cockerham's raspiness and Barbara Gaskin's sweetness. Cockerham's voice reminds me of a cross between Dylan and Lydon/Rotten (if such a thing is possible) and on it's own it might be to ugly for this type of music, but combined with Gaskin's voice that might be too cloying on its own, a unique combination happens. "Old Boot Wine" has a more rock vibe than their previous LP "St Radigunds" and at times reminds me of certain motorific grooves of certain Germanic 70s groups. If you have already Pentangled and Fairported it might be time to Spirogyra. They're the best band that I've discovered in a while. I've been into 60s and 70s underground music for a long time and its always cool to find amazing stuff from this era that blows your mind.