Tubular Bells 1973 - Mike Oldfield (Instrumentals!), the entire album is good way to test the sound.
Superstar Pt Zero - K-os, jazzy, hiphop, samples and more in one wonderful winding track.
A Rush Of Blood To The Head - Coldplay, the entire album is a good way to test the sound.
Blues For The Red Sun - Kyuss, the entire album is a good way to test the sound especially with '50 million year trip (downside up)' and 'Apothecaries' Weight.'
Satsuki - Kagrra, J-Rock with some great musical transitions.
Omou - Kagrra, the same for 'Satsuki,' play these the two Kagrra tracks in sequence starting with 'Satsuki.' These two tracks complete eachothers sound.