Optiplex 3020 SFF

I'm trying to connect Dell Zylux a525 speakers to the Optiplex 3020 SFF and I see there is a speaker/line out port on the back and a port on the front. I'm finding that the port on the back causes the audio to be very bad and hollow, whereas the port on the front sounds great. It appears the port on the back is "line out/speaker out" and the port on the front is "speaker out." This means the port on the back is not amplified? Is there anyway to change this so I can just plug the speaker cable into the back?