Imagine cracking into a sampler CD that exhibits all of hardcore metal’s stylistic triumphs from the past 20 years or so. Chicago’s American Heritage has created this with Sedentary, the follow-up to the group’s critically acclaimed 2006 release, Millenarian. That album’s release and subsequent tour left the band short a bass player, a void that most groups would try to fill before recording a new LP. American Heritage decided instead to go ahead with the recording, using a roster full of metal’s powerhouse bass players.

The outcome from this strategy is a group of 11 songs that dance through a good amount of metal’s subgenres, from grind to sludge to hardcore while still finding the time to get around to an epic ballad. Many of the songs showcase the band’s versatility. During “Kiddie Pool Of Baby Blood” for instance, the band seamlessly controls a Black Flag, hardcore-style song. This is immediately followed by the Melvins-like sludge/punk “Fetal Attraction,” where the band receives some bass help from Mastodon’s Bill Kelliher. The transition is completely seamless. Neither of the songs sound contrived so no one will be thrown off by the switch.

There are other instances, however, that sound more like tepid explorations than showcases for the band’s genre-bending chops. “Sickening Rebellion” sounds much less inspired than the previously noted hardcore success. But slight dips in focus can easily be forgiven with songs like “Vessels/Vassals,” a sludge-metal song with a melodic focus, even if it is coming from vocal chords that sound like they have been tempered by shots of broken glass. The well-placed closer, “WWDHD,” centers on composition and experimentation with its use of synths and samples. The difference from the adrenaline-fueled first 10 tracks makes it an obvious highlight on the album.

The bass player situation with the band is a strange one, and the use of so many session musicians to fill the empty slot suggest that American Heritage was hosting an audition. It may have been, as Erik Bocek, the guest bassist on “Abduction Cruiser,” was chosen as the band’s new full-time member. Securing a permanent bassist is a happy outcome for the group, but the constant lineup-changes on Sedentary prevent the band from establishing its own unique sound. Yet despite the album’s heavy reliance on songs rooted in metal’s past successes, it still manages to sound awesomely fresh.