Predating Embryo's move into funky ethnic fusion by about three years, Opal exudes a kind of jazz-inflected psychedelic-rock feel. Through the years the band has been regularly compared to Can. The comparison makes sense when first encountering a track like "You Don't Know What's Happening," which sounds not far removed from the iconic Tago Mago. At the same time, Embryo bust way more skronk than their Krautrock peers. The group's grooves are also less fluid, more like stuttering pistons than purring motorik. To hear the band at its peak, go straight to "People from Out the Space."