For over two decades, MxPx have combined a frenetic punk attack with substantial melodies and serious lyric content. The latter two qualities come shining through on Acoustic Collection, released in conjunction with the trio’s 22nd anniversary as a band. Members Mike Herrera, Tom Wisniewski, and Yuri Ruley strip their material down to bare essentials, giving these tracks the feel of a back-porch jam. Including tunes from early albums like 1995’s Teenage Politics as well as recent releases like 2012’s Plans Within Plans, the threesome revisit the volatile feelings of their younger days and reconsider old yearnings with a new maturity. Backed by acoustic guitar, Herrera gives such MxPx classics as “Doing Time,” “Never Better Than Now,” and “For Always” heartfelt readings that find fresh meanings in familiar words. The post-adolescent musings of “My Mom Still Cleans My Room” take on a special poignancy in this setting. Tsunami Bomb’s Agent M lends her vocals to help bring out the bittersweet undercurrents of “Tomorrow Is Another Day,” “Secret Weapon,” and “Aces Up.”