1990: "Souls of Black", Testament

It's really not until you start getting to the second tier thrash bands of 1990 that the wear and tear starts to become apparent. Suicidal may have had a career year, but the rest of their not-ready-for-primetime brethren weren't faring so well. Testament was never a household name, but the previous year's Practice What You Preach found no fewer than three music videos gracing late night MTV, and the enhanced visibility garnered them a support slot on 1990's legendary Clash of the Titans tour with Slayer, Megadeth and (who else?) Suicidal Tendencies. The so called "Big Four" of thrash included Metallica and Anthrax in addition to Slayer and Megadeth, but the Clash of the Titans lineup made a pretty good case that if things were expanded to a "Big Six", ST and Testament would fill the vacant slots.

Though the band were still technically touring on the back of Practice What You Preach when the tour began, most considered the hasty follow up, Souls of Black, to be somewhat of a letdown. In hindsight it's a fine album, well executed and cleanly produced, but the lack of prep time obviously curtailed the band's ability to craft hooks with the same consistency they'd been used to.

And really that's the recurring theme of this beginning of the end for thrash: there wasn't a decline in popularity at this point - if anything 1990-1992 was a peak era for interest in thrash metal - but that popularity often resulted in rushed production schedules and a forced demand for quick product. The end result was a flurry of diminishing returns over the next few years which resulted in die hard fans tuning out, favoring instead the new trump card in extremity that the death metal bands were offering.

It should also be noted, however, that later in 1989 the influential late night MTV program "Headbanger's Ball" was cut from three hours to two; the heavier, less commercial bands were largely relegated to that third and final hour, so when it was 86'ed that left room for only a token handful of thrash videos per night... and it wasn't like true metal (as opposed to glam) was getting airplay outside the confines of "Headbanger's Ball". In an era when a lot of headbangers were farm belt kids who relied on MTV to sample new metal, that would turn out to be a fateful decision.