Over the decades, Sepultura have continuously cranked out their own tried and true metal, with no big frills or ego. Here on their 15th studio album, Quadra, we find them working just as hard as they always have, and in monster vocalist Derrick Green’s opinion, prouder than they ever have been. Quadra is a concept record, based on the liberal arts of the quadrivium (look it up). Simply put, they were really digging on the number four. The 12 tracks are broken down into 4 sections that explore the Brazilian-based band’s styles. Beginning with thrash, then moving into groove, then a more progressive sound, and finishing with melodic songs. In typical Sepultura fashion, there are also epic elements in the production, from their trademark percussion whirlwinds, to a full on choir. Not an album from these guys goes by without being politically charged, and this is no different. Even laying down a tribute to Muhammad Ali, and his sacrifice for his beliefs. These headbangers don’t stop, and likely won’t stop.