There's something to be said for playing straight-ahead post-punk without a bassist. Bands like Lightning Bolt and Orthrelm get some serious noise out of their guitars and drums, but Massachusetts-based Sinaloa are more interested in sticking to standard song structures. Footprints On Floorboards is far closer to the DC sound of bands like Rites Of Spring and Q And Not U and the hardcore of 400 Years and Sleepytime Trio; Peter Zetlan and Brendan Campbell's angular guitars chase each other around Lucas Pearson's pounding drums, and the screamed vocals would be overwrought if they weren't so passionate.

Sinaloa's passion, indeed, is the trio's biggest touchstone. "November's Unanswered Questions" appears to be a common defeatist tale about the morning after 2004's presidential re-election, but this one is tempered with a third grader's innocent disbelief: "The little ones know more than we ever will / ... / My heart is heavy, full and defeated / Dismal because your words hit so true, and I was speechless." The wrenching lyrics smash through the music, giving shape to otherwise faceless songs.

The lack of a bass is noticeable, although the trio entertains a double-bass player guest on "Polar Bears And Clubs" and closer "With Our Ears To The Soil", and a trombone on "Regard To Structure". Most songs simply lack the bottom end that typically grounds the music: Sinaloa have consciously left that permanent hole in their sound to remind them of a good friend who would have played bass, but passed away. "Words Through Wires"'s tells of that terrible morning, with the worst wake-up call imaginable: "Trouble came to me early / This morning as I rose from bed / Without knowing it / Hung up that receiver / And it whispered words I had never heard."

Footprints On Floorboards's CD booklet includes an explanation of every song: "Polar Bears And Cubs" is an ode to family, "Static"'s take on the psychologically draining corporate work environment will be familiar to current and former cube jockeys, and "With Our Ears To The Soil" is a nostalgic look back upon a young life and the riches that transience brings. You could argue that such explanations kill the music's mystique, or remove our own imagined meanings from the process, but most listeners will appreciate these definitive interpretations.

Sinaloa's adrenaline and emphatic passion make up for any perceived holes in their music, deliberate or otherwise. The band, which takes its name from a state in Mexico, performs as a collective: everyone sings and the lyrics are uncredited. As a result, Footprints On Floorboards is a unified emotional vision, deep in resolve and impressive in scope.