Celtic metal, from the outside in. Each step is a genre and the single record this encyclopedia would put on first. Play them in this order and the last one should sound like a next step rather than a wall.
- 1 The way in
Heavy metal 1970
It split off from hard rock and blues rock when Black Sabbath tuned down and wrote riffs on the tritone. Volume, riff and a code of its own - every branch below starts here.
Sung. Melodic singing throughout.
Put on
Black Sabbath - the song Black Sabbath. The first thirty seconds are the genre's birth certificate.
Black Sabbath, Black Sabbath (1970) - 2 Then
Folk metal 1993
Traditional instruments and folk melodies built into metal. Every region has written its own version.
Sung and screamed. Clean singing and harsh vocals trade off, often chorus against verse.
Put on
Finntroll - Nattfödd. Black metal at Finnish polka tempo, and it works.
Finntroll, Nattfödd (2004) - 3 What you asked about
Celtic metal 1994
Irish melodies and traditional instruments over black or heavy metal.
Sung and screamed. Clean singing and harsh vocals trade off, often chorus against verse.
Put on
Primordial - The Gathering Wilderness. No tin whistle, and the most Celtic of the lot.
Primordial, The Gathering Wilderness (2005) - 4 Where to go next
Hard rock 1968
Louder volume, thicker riffs, vocals pushed to the edge. Heavy metal splits off from it, but hard rock stays closer to the blues and to the chorus.
Sung. Melodic singing throughout.
Assembled from the tree: every genre Celtic metal descends from, in order. Celtic metal has no subgenres, so the last step is the genre that rates closest to it by sound.