The new generation of streaming music services like Spotify, Rdio, and MOG have more music than you could consume in a lifetime. But how much of it would you really want to listen to?

There’s no shortage of great roundups and reviews showing the pros and cons of each service, but they rarely talk specifically about the different music you can find on each. They’ve all built impressive catalogs, but it’s nearly impossible to tell from casual browsing which artists and albums are exclusives for each.

Fortunately, both Rdio and Spotify offer powerful developer APIs, making it simple to compare the two. (Sadly, MOG doesn’t offer an API, so isn’t included.)

For this test, I needed a large set of popular, well-loved albums to test. I used the top 5,000 albums from Rate Your Music, the quirky 11-year-old online community dedicated to rating and reviewing music. These albums span all genres, from klezmer to chiptune, with a total of 2,282 different artists across 70 years of recorded music.

I used the Spotify and Rdio search APIs to look up each album, and checked their streaming availability in the United States. (Rdio uses the IP address to determine country of origin, making it impossible to query other countries. Spotify, on the other hand, returns a list of every region the album’s available.)

Note: The results aren’t perfect. Spotify and Rdio often have slight differences between artist and album names, which can deliver false positives. Let me know if you spot anything amiss and I’ll correct it.

Results

Of the top 5,000, about 44% were available on both Spotify and Rdio. 4.8% of the albums were only available on Spotify, while a further 6.8% were only available on Rdio. Overall, 56% of the albums were streamable on at least one of the services.

Labels are still withholding most or all of the albums from many popular artists. The Beatles, King Crimson, AC/DC, The Eagles, Tool, De La Soul, Peter Gabriel, Led Zeppelin, and Metallica are nowhere to be found, as well as most of the best albums by The Kinks. Music geeks will be sad to discover that Frank Zappa, Coil, Spacemen 3, and Joanna Newsom are all missing, as well. This landscape will constantly shift as labels change their minds; Arcade Fire was added to Spotify yesterday, and more than 200 indie labels left the streaming services last month.

But what about albums that are exclusive only to one service? The results surprised me. Spotify has a reputation for having a deeper catalog, but at least for historic critically-regarded albums, Rdio has a better selection of both popular and obscure artists. More albums in the top 5,000 were available on Rdio, and they offer exclusive access in the U.S. to huge acts like Bob Dylan, Pink Floyd, the White Stripes, and Queen.

Top Exclusive Artists

Here’s a list of the top 20 artists exclusive to each service, with the number of exclusive albums in parentheses.

Only on Rdio	Only on Spotify
Bob Dylan (12) Pink Floyd (8) Bruce Springsteen (7) Miles Davis (6) The Gathering (5) Blind Guardian (4) Can (4) William Basinski (4) Iced Earth (4) Stars of the Lid (3) The White Stripes (3) John Williams (3) Queen (3) Nevermore (3) Thelonious Monk (3) Charles Mingus (3) Bill Hicks (3) John Coltrane (2) Camel (2) Keith Jarrett (2)	My Dying Bride (4) Miles Davis (4) Candlemass (3) Funkadelic (3) The Pretty Things (3) Current 93 (3) Darkthrone (3) Underworld (3) Katatonia (3) CunninLynguists (3) Charles Mingus (2) Mahavishnu Orchestra (2) The Jesus Lizard (2) The Misfits (2) Klaus Schulze (2) John Coltrane (2) Galaxie 500 (2) Silvio Rodríguez (2) Secos & Molhados (2) maudlin of the Well (2)

Note that artists like Miles Davis and John Coltrane appear on both lists because of how prolific they were. Both are well-represented in Spotify and Rdio, but some critically-adored out-of-print albums are unavailable on both.

Top Exclusive Albums

Digging into the albums, Rdio wins again. Nine of the top 100 albums are only found on Rdio, while only one is exclusive to Spotify. In fact, there are only 32 albums in the top 1,000 available on Spotify alone. Below is the top 30 for each service, along with their Rate Your Music ranking.

Only on Rdio

Only on Spotify

Pink Floyd – The Dark Side of the Moon Pink Floyd – Wish You Were Here Bob Dylan – Highway 61 Revisited Bob Dylan – Blonde on Blonde The Clash – London Calling Bob Dylan – Bringing It All Back Home Bob Dylan – Blood on the Tracks Pink Floyd – Animals Bob Dylan – The Freewheelin’ Bob Dylan Bob Dylan – Another Side of Bob Dylan Bob Dylan – The Times They Are A-Changin’ Dr. Dre – The Chronic Stars of the Lid – The Tired Sounds Of Camel – Moonmadness The White Stripes – Elephant Bon Iver – For Emma, Forever Ago John Williams – Raiders of the Lost Ark Popol Vuh – Hosianna Mantra Jethro Tull – Nothing Is Easy: Live at the Is… Albert King – Born Under a Bad Sign Keith Jarrett – Vienna Concert Dead Kennedys – Plastic Surgery Disasters Thin Lizzy – Black Rose: A Rock Legend Magic Sam – West Side Soul Bob Dylan & The Band – The Basement Tapes Eric Dolphy – Out There Blind Guardian – Live Devin Townsend – Terria Strapping Young Lad – City Pretenders – Pretenders

The Zombies – Odessey and Oracle Candlemass – Nightfall Funkadelic – Standing on the Verge of Getting… The Jesus Lizard – Goat The Pretty Things – Parachute The Jazz Composer’s Orchestra – The Jazz Comp… Klaus Schulze – X Sodom – Agent Orange Danny Elfman – Edward Scissorhands Galaxie 500 – Today Current 93 – All the Pretty Little Horses Secos & Molhados – Secos & Molhados maudlin of the Well – Bath Sun Kil Moon – Ghosts of the Great Highway Anathema – Alternative 4 Darkthrone – A Blaze in the Northern Sky The Byrds – Fifth DimensionMost Popular The Gun Club – Miami Autopsy – Severed Survival My Dying Bride – Turn Loose the Swans The Jesus Lizard – Liar Vektor – Black Future maudlin of the Well – Leaving Your Body Map Jean Michel Jarre – Oxygene 16 Horsepower – Secret South Riverside – Out of Myself Darkthrone – Transilvanian Hunger Nino Rota – Amarcord Suede – Suede Darkthrone – Under a Funeral Moon

Unless you’re a huge fan of Norwegian death metal, it’s hard to see this as anything but a win for Rdio. The fact is that both services have done a tremendous job of building the celestial jukebox — with a couple of high-profile exceptions, nearly everything you’d ever want to listen to is available at your fingertips.

Now, one huge drawback of using the Rate Your Music list is that it skews towards older album-oriented music geeks. That’s great if you like Ornette Coleman and Galaxie 500, but not so great if you like Drake and Katy Perry.

Next week, we’ll set the controls for the heart of mainstream music: the Billboard charts, analyzing every charted single in the top 100 from 1955 to the present. This will give us a completely different view of their catalogs, focused on pop singles, past and present, instead of classic albums.

Want more? Ed Summers did his own fascinating deep-dive into Spotify and Rdio uses top album lists from Alf Eaton’s Album of the Year list collection, and published the results on Google Fusion Tables. Also, try Matt Montag’s Music Smasher, a tool that searches Rdio, Spotify, and Grooveshark.

(Note: This was originally published for my Wired column.)