The departure of Maniac and the return of Attila to Mayhem yielded this intriguing album, in which the band take the technical lessons they had learned on Grand Declaration of War and Chimera and applied them to grimy, lo-fi black metal, yielding one of the sickest-sounding albums of their career.
Whereas many black metal albums recorded with deliberately poor production focus on creating a "tinny" noise (think Ulver's Nattens Madrigal or Darkthrone's Transilvanian Hunger), Ordo ad Chao on first listen sounds muffled, murky, and bass-heavy - however, I find that soon enough my ear adjusts to the production and I can detect intriguing nuances in the playing. As good as the musical performance is, once again I have to say that - as with De Mysteriis Dom Sathanas - what really makes the album for me is the absolutely unhinged vocal performances of Attila, who works through an absolutely insane range of vocal styles over the course of the album.
As a matter of fact, the album lyrics are actually rather silly - they're more or less all based on New Age UFO conspiracy theories as promoted by the likes of David Icke, believe it or not - but Attila is able to make them sound like the most evil thing in the world, just as the band use their newfound technical expertise to finally accomplish depths of disorienting musical blasphemy which their previous album with Attila only hinted at. Give it a chance, because I for one found it grew a LOT on me.