Reddit mentions of Best Home Fashion Basic Thermal Insulated Blackout Curtains - Antique Bronze Grommet Top - Navy - 52" W x 84" L – (Set of 2 Panels)

Honestly, I got some on craigslist for $20. I just emailed and made sure the previous owners didn't smoke or have pets.

Try to get something like this curtain I found on Amazon. It has reinforced grommets for easy and durable sliding and it looks thick. "Blackout" means it's woven densely enough to block sunlight out, which means it should be "heavy" enough to absorb sound. That silence you get when you put your ear up to the panelling you have should be replicated if you put your ear up to the curtains.

If you happen to find lots of thinner curtains for cheap, just layer them.

Velvet curtains would be ideal but you're an audiophile in college. You probably already sold a kidney for the setup you currently have. Buy the curtains on craigslist, buy this $10 pole (make sure the grommets on the curtains are big enough for the pole, though they should be), and whatever mounting hardware you and the homeowner can agree on.

I can't promise that this will fix everything but a treated room allows for much easier adjustments and better critical listening.

I used these in navy blue for a while and was happy with them. Some light did come in at the sides because of how my curtain rods hung but I never noticed any through the curtains themselves. It wasn't enough to wake me up or keep me awake but YMMV.