Julian Cope presents Head Heritage

Most of the stuff before Omnio involves a bit of screaming. That's Black Metal screaming, rather than Death Metal growling (like you get with Opeth, although you can actually understand what Mikael Åkerfeldt is saying most of the time, unlike most other gruff vocalists).

If you like Omnio, I'd recommend - instead of going backwards with In the Woods... - Weiland by Empyrium, Kveldssanger by Ulver and Light of Day, Day of Darkness by Green Carnation. The latter is a prog-metal meisterwerk featuring one epic sixty-minute track. Glorious stuff!