While almost every indie label offers up a couple sample MP3s from a given artist, Secretly Canadian trumped them all last spring by posting a free zip file of an entire Impossible Shapes album. Supposedly recorded as the “sister album” to last year’s Horus, Tum sold a few hundred vinyl copies on the St. Ives label and got downloaded by a handful of Shapes fans. Now SC is finally giving the album a full CD release, in obvious recognition of the fact that not nearly enough people heard how stunning it is. Heavy on instrumental tracks and song fragments, not to mention only lasting about a half hour, Tum can feel unfinished at its worst. But at its best, the album is a fantastic throwback to late-60s classic rock. With ten whole songs tied together by a string of interludes mutating the same haunting melody, the album as a whole almost overshadows its predecessor. At least now, the two have an equal shot at getting heard.