Isis has the dubious distinction of being too influential for their own good. Formed in Boston, the quintet picked up where Neurosis and The Melvins left off, crafting lengthy, repetitive songs full of ponderous, gradual builds. This new approach to metal songwriting spawned a roiling mass of instrumental imitators, all trying to capture the titanic crescendos and meticulous dynamics that made the band so popular. United under the banner of “post-metal,” the scene was soon chock full of clones.

[audio:|titles=20 Minutes/40 Years|artists=Isis] Isis – “20 Minutes/40 Years”

It’s hard to blame the innovators for all this aping, and Isis still stands above the fray on the strength of distinctive, warm guitar tones and a keen ear for melody. New album Wavering Radiant is another strong example of inventive, atmospheric songwriting, matching the band’s crushing riffs with a limber musicianship that abets the complicated arrangements. As the band continues to develop, eerie interludes have come into their own alongside their traditional riff-earthquakes.

Founding guitarist Aaron Turner is also the progenitor of Hydra Head Records, which has established itself as a premier label for all that is heavy, but also quirky. Featuring many artists Isis-like and not, Turner’s dual responsibility keeps the band at the center of a scene, independent of their musical inspiration.

The show at the Great American on Tuesday will feature labelmates Helms Alee and Mammifer (another Turner project), providing a three-Hydra-headed dose of captivating, mostly instrumental metal. Expect stately progressions and epic shifts, with the occasional moment that sounds like planets exploding in slow motion.

The show is $16, starts at 9pm and is 6+