It is with some degree of nobility that the excellent Alt-MC Santogold and the superb DJ and MIA producer Diplo meet to unleash their own mixtape on the internet, and all completely free of charge. The two prove to have excellent and widespread taste as well, as the mix veers wildly from shouty soul diva Aretha Franklin to jerky post-punk oddballs Devo. The main theme however appears to be somewhat underground hip-hop and rap, occasionally mixed into more mainstream stylings. The mix itself kicks off with Oscar-winning (honestly) hip-hop collective 3-6 Mafia with a superbly staccato remix of Late Night, featuring Salt ‘n’ Pepa style beats and bratty exchanges, which stealthily integrates seamlessly into a buzzy, bassy mix of Santogold’s feisty, dubby Shuv It. Santogold herself understandably appears repeatedly throughout the mixtape, whether she’s trading rhymes with Amanda Blank (sounding like a snottier Princess Superstar) on I’m A Lady or MIA and Gorilla Zoe on the elusively rare and tribal-sounding Radioclit remix of Get It Up.

Like any good mixtape, genres are treated with reverence and given their own space, and like a good pair of fashionistas, Diplo and Santogold never shy from exploring the very outskirts of the cultural zeitgeist. Even producer du jour Mark Ronson appears in a self-parodying skit with Santogold, discussing a parodic re-jigging of Santogold’s excellent Creator. Creator itself, easily the greatest single of 2008 so far, is destroyed and rebuilt later in the mixtape as a grime classic, with the familiar out-of-control bass wobble and submarine beeps given rave horns and a rap crew who proceed to distort and bend it out of control. It’s superb, and even a drop into Souljaboy’s idiotic Crank That seems welcome. Another rule of the good mixtape, to keep things unexpected, is therefore adhered to perfectly. The painfully fashionable genre of dubstep is also given an outing with the incredibly stoned combination of top names Banga and Skream. Sounding like two-step garage with a slowed-down heartbeat and a twenty-bag of very strong skunk, it’s an entertaining and highly appropriate introduction to an emergent genre.

All this hipster music is wonderful, but Santogold and Diplo are careful to include the old skool in with the new. Frequently taking a trip to the wonderful world of 1990 hip-hop, Sir Mixalot with Posse on Broadway in particular is a highlight, evoking images of flat-tops, ghetto blasters and lowriders. There’s some superb taste in ancient-sounding reggae and ska too, with legends like Desmond Dekker, Cutty Ranks and Barrington Levy providing the echo-drenched and sublimely bassy dub vanguard. Even new-wave superstars The B-52’s and the still-exceptional Clash make appearances, with the classic Mesopotamia and Ghetto Defendant respectively.

It’s a frequently thrilling and well-chosen mixtape, and to make even the mildest complaint that it’s a little overlong is blown to bits by the fact that it’s absolutely, one hundred percent free - and not even in In Rainbows' free-but-not-really-free style. Download it, if for some reason you don’t like it delete it, but for the rest of us it’s proof that sometimes not only is there such thing as a free lunch, but it’s given a well-chosen and heartfelt soundtrack to boot. Read more on Last.fm. User-contributed text is available under the Creative Commons By-SA License; additional terms may apply.