In 2013, frontman of Grammy- nominated American band Lamb Of God, Randy Blythe, was acquitted of a manslaughter charge by a Czech Republic court.
By then, the singer and primary lyricist had already spent time in an Eastern European jail, accused of having caused the death of a fan who fell off the stage during the band's show in the country three years earlier.
For VII: Sturm und Drang, the quintet's seventh album (eight if you count their first under a different moniker), Blythe tapped his experiences in a foreign penitentiary.
One would expect words of despair and anger at having to endure incarceration on a wrongful charge, but his lyrics on the album, named after the German term for "storm and stress", take on a more expository tone.
Songs such as Still Echoes delve into the dark history of Prague's Pankrac Prison ("a tarnished heirloom / Passed down through iron fists") while #512, which was his cell number, recounts his life-changing experiences there ("Six bars laid across the sky, Four empty walls to fill the time / My hands are painted red / My future's painted black").
Lamb Of God
Epic / Nuclear Blast
Musically, the album contains more of what vaulted Lamb Of God into the metal big leagues - extremely precise and convoluted riffs that balance complexity with focused intensity.
It is their tightest collection of songs yet, where blast beat drums duel with talkbox-life effects on guitar solos.
Soulfly, another titan of the metal world, have a new album that harks back to the glory days of metal in the late 1980s and early 1990s.
The band's main man, Brazilian singer/guitarist Max Cavalera, was a progenitor of the sub-genre known as groove metal, which tempered heavy, mid-tempo riffs with speed and ferocity.
Lamb Of God were part of the New Wave of American Heavy Metal from the early 2000s which incorporated groove metal and popularised it to a new generation of metalheads.
Cavalera keeps it in the family with Archangel. His son Zyon plays drums and other children such as Richie and Igor contribute vocals on various tracks.
The themes get heavy, referencing ancient deities and biblical themes, but at the same time, the band also do a cheeky cover of Napalm Death's notorious one- second song, You Suffer.
The title track is an industrial monster, with clattering drums and shrill guitars reminiscent of 1990s era industrial acts.
Despite its title, opening track We Sold Our Souls To Metal owes much to the frontman's punk and hardcore roots through its rapid beats and rushed verses.
The album clincher must surely be Soulfly X, where Cavalera digs even deeper and incorporates decidedly non-metal instruments such as the sitar, flamenco guitars and the duduk, a type of ancient flute.
Juggling all these genres into a coherent metal album can be a nightmare, but in Cavalera's deft hands, Archangel is a satisfying brew of headbanging anthems.