Heard It on the X by studio super group Los Super 7 (this time featuring Freddy Fender, John Hiatt, Lyle Lovett, Rick Trevino, and a bunch of others) is intended to be a celebration of the maverick border-radio stations that broadcast out of Mexico from the ’30s through the ’60s. It’s a bit too slick to suggest the anything-goes aesthetic of those far-reaching frequencies, but as middle-aged party records go, it’s definitely above average. The highlight is “The El Burro Song,” one of two numbers performed by Mavericks leader Raul Malo with backing from nominal indie rockers Calexico, who appear throughout the album. Written by Calexico’s Joey Burns (with an instrumental finale from Silvestre Varga’s songbook), “Burro” is a funny-sad mariachi pop tune about a heavy-drinking paramour (“My love has fallen and can’t get up...her heart like a radio with the sound turned down”), sung with Malo’s typical yearning and played with unfussy, genre-spanning confidence (though it could stand to sound a tad more intoxicated). Someone should really get these guys to do a whole album together and not waste time about it.