So i just got a bass, and im wondering how you go about learning bass lines by ear. With guitar, it's "easy" since you can hear them pretty clear, but bass just usually just gets drowned out and you can hardly hear it. Is there something I can use to make the bass guitar more prominent in songs?
Listen to CKY.
well, yeah. i'm using audacity and the only thing i can really accomplish with the EQ is making a song soudn like shit.
Listen to CKY.
Get some good speakers/headphones.
Fender Precision Bass
Fender Jazz Bass
1967 Fender Coronado Bass II
Warwick Star Bass
Squier Precision Bass TB
open up in the media player of your choice (WMP is great for this)

bring down every level except for around 150-250. boost those. this is where you're going to get a lot of bass clarity. anything lower than 150 is probably actually going to hinder the process since it'll be so boomy you can't really discern the notes/intricacies of the line.
Get some speakers/headphones with a clear low range.

Or be lazy like me and just learn the chords and improvise ahead
Professional lurker since 2009.
Your ears will also "adjust" to listen to the bass. Its normally fairly easy for me to hear the bass line in a song (doesn't mean I can play it tho) This is just your ears learning to listen more closely. Musicians hearing is greater than the casual music fan, as far as frequency range and pitch, time, timbre, etc.

Try starting on really simple songs where the bass is out front in the mix