by Alex Henderson 　　It's a familiar story in the metal world: band experiences countless personnel changes, band has a hard time maintaining a stable lineup, band unveils new lineup on new album, fans either breathe a sigh of relief and applaud new lineup or complain that band has lost it and gone to hell. Thankfully, Threat Signal's fans can breath a sigh of relief when they hear Vigilance, the Toronto metalheads' second album. Threat Signal had plenty of lineup changes after their 2006 debut, Under Reprisal -- and on Vigilance, lead singer Jon Howard is the only one remaining from the Under Reprisal lineup. But the good news is that Threat Signal bounces back nicely on this 2009 release. Stylistically, Vigilance isn't a major stylistic departure from the Canadians' first album; their work is still best described as alternative metal with elements of metalcore/hardcore, thrash metal and death metal, and they still draw on influences that include Fear Factory, Meshuggah, Lamb of God, Slayer, and As I Lay Dying. Vigilance is scorching much of the time, but it is also relatively melodic and not without nuance. Howard usually favors metalcore/hardcore-style screaming vocals, although there are some clean vocals as well. While Vigilance isn't full-fledged metalcore, the album's lyrics have a strong hardcore aesthetic. Memorable tracks like "United We Stand" and "Revision" have that "angry as hell, but positive and hopeful" vibe that is so common in metalcore and hardcore. In fact, Vigilance is memorable more often than not. There are a few mediocre tracks, but overall, this sophomore outing underscores Howard's ability to keep Threat Signal healthy despite all those lineup changes.