I've got a Steinburg UR22 interface and picked up some used Audix MM-15 passive monitors at my local brick and mortar. The interface has 1/4" monitor outputs but the monitors just take plain old speaker wire. The music store and Radioshack haven't been of much help, am I just gonna have to take a 1/4" cable, take off one adapter and connect the wires straight to the monitors?
The monitors you have are passive. They still need an amp to work. Buy an amp for $200 or better yet... get a modern pair of powered monitors. M-Audio 40s are around $130 and are a pretty good bang for the buck. Another $200 will get you some KRK Rokit 6s which are a nice step up.
"Your sound is in your hands as much as anything. It's the way you pick, and the way you hold the guitar, more than it is the amp or the guitar you use." -- Stevie Ray Vaughan

"Anybody can play. The note is only 20 percent. The attitude of the motherfucker who plays it is 80 percent." -- Miles Davis

Guthrie on tone: https://www.youtube.com/watch?v=zmohdG9lLqY
If you really are on a tight budget get a Lepai a2020+, though a nicer pair of monitors like the ones suggested would work better imo.
Name's Luca.

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Clue: amplifiers amplify so don't turn it on if you need quiet.
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