At seven songs long, Dead Black Hearts’ second EP, The Southern Front, plays more like a mini album. The Austin, Texas, quintet specializes in mellow indie rock, citing bands like Bright Eyes, Wolf Parade, Radiohead, Led Zeppelin, and The Flaming Lips as influences. Some deep, rumbling bass lines set the stage for the subdued opening tune, “Ambush!,” as three-part vocal harmonies crystallize over a brushed snare drum before a baritone guitar solo provides spooky tones. The piano-heavy ditty “Postcard from Somewhere Cold” flirts with latter-day Beach Boys-inspired baroque pop (think Wild Honey or Carl and the Passions). The following “Spit Shine” makes good use of vocal reverb and nasal-toned singing to echo Pacific Northwest guitar pop. Jonny Greenwood–influenced guitar and distorted Wurlitzer notes give a heady cool to “Out the Way You Came In,” while “Married to the Sea” works in some angular herky-jerky post-punk inspirations. “5 to 9” closes, sounding more like Arcade Fire than Dolly Parton’s 1980 hit played backward.