It took a couple of years to compile but Southern Lord recording artists Sunn O))) have finally completed their seventh full-length effort, Monoliths & Dimensions. And, as expected, its release this May will further push the boundaries of drone metal.

Once again, guitar duo Stephen O’Malley and Greg Anderson ensure that their unsual amalgam of metallic sub-genres — they are often admired for incorporating dark, ambient, black and noise metal into their original sound — is offset and accented by a host of guest musicians who bring their idisyncrasies to the table.

This time around, the roster of luminaries is rather strong and decidedly diverse. The likes of composer Eyvind Kang (notable for his work with John Zorn, Marc Ribot, Bill Frisell, etc.) offers a perspective on acoustic ensembles, Australian guitar genius Oren Ambarchi, Mayhem/Tormentor vocalist Attila Csihar and Earth’s Dylan Carlson, Julian Priester (who’s worked with Sun Ra, John Coltrane’s African Brass band and Herbie Hancock’s Sextant band) and new music hornplayer Stuart Dempster all contribute to Monoliths Dimensions.

O’Malley and Anderson have also expanded on their sound via an upright bass trio, French & English horns, a harp and flute duo, piano, brass, reed and strings ensembles and a Viennese woman’s choir led by Persian vocal savant Jessika Kenney.

However, as Southern Lord forewarns, “The album is not Sunn O))) with strings or metal meets orchestra material. The band took an approach concentrating on more of allusion toward the timbre of feedback and the instruments involved, so the piece is really illusory, beautiful and not entirely linear. The band state the end product is “the most musical piece we’ve done and also the heaviest, powerful and most abstract set of chords we’ve laid to tape.”

Monoliths & Dimensions tracklisting:

1. “Aghartha” (17:34)
2. “Big Church [megszentségteleníthetetlenségeskedéseitekért]” (09:43)
3. “Hunting & Gathering (Cydonia)” (10:02)
4. “Alice” (16:21)

I can’t wait!