It was three decades ago that Mickey Hart stepped out from behind the Grateful Dead and created his first global drum project onDiga Rhythm Band. That album still sounds as fresh and vibrant today as it did in 1976, when it was received more as a curiosity than the world-music prophecy it turned out to be.  Hart and his rhythm partner fromDiga, tabla titan Zakir Hussain, reworked the concept for theirPlanet Drumalbum in 1991, and they now return withGlobal Drum Project. It's an CD that continues Hart's infatuation with electronic toys and their percussive possibilities as he mixes samples and MIDI-triggered electronics into the works. WithPlanet Drummers Sikiru Adepoju and Giovanni Hidalgo plus Taufiq Qureshi joining in, there's little doubt thatGDPis a groove-centric album.  After the exultant opening track "Baba," featuring Babatunde Olatunji, the soul of the originalPlanet Drum, sampled posthumously, most tracks settle into dark, swampy, steady-state grooves.  Sampled rhythmic singing from Zakir punctuates "Under One Groove," while "Heartspace" adds sarangi and sitar for a more Eastern, meditative space. It isn't the virtuoso rhythm workout you might expect, but neither is it the orchestrated percussive percolations ofDigaorPlanet Drum.  Instead, it's a chilled electro-percussive jam session with looping grooves oscillated by electronics and cut with a digital razor.--John Diliberto