Speakers Logitech Z313 2.1

Just got them, but they don't have a bass control I realized which is important to me. They're 34$ new. Pickup on campus.

https://www.amazon.com/Logitech-980-000382-Z313-Speaker-System/dp/B002HWRZ2K/ref=sr_1_1?s=electronics&ie=UTF8&qid=1502170905&sr=1-1&keywords=z313