If the darlings of the summer festival circuit were jumbled together into some populist dream band, it might sound like New Jersey combo River City Extension.

If the darlings of the summer festival circuit were jumbled together into some populist dream band, it might sound like New Jersey combo River City Extension.

Imagine a boisterous (but not too boisterous, let's be reasonable here) folk-rock band in the vein of Mumford & Sons. Adorn it with the celebratory horns and guy-girl vocal dynamic of Edward Sharpe and the Magnetic Zeros but sung with the emo affectation of Matt & Kim. Paint with the broad scope and oversized lineup of Canadian collectives Broken Social Scene and Arcade Fire.

Rumba can handle a band of that size, but it's unclear whether the bar can contain their enthusiasm, especially with the rambunctious Trains Across the Sea on hand to open.