"You can always split the audio coming out of your computer and run it separately to both the powered speakers and your Polk sub."
----How would I split the audio? Would a cheap DAC like the Behringer UCA202 work? Regardless, would you recommend I buy a cheap DAC like the Behringer UCA202?
"The problem is that you'll then need to set the low pass filter on the sub to the low roll off of the speakers, whereas you might get better bass from your setup using a higher crossover on the speakers."
----How do I look up the look up the low roll off of the speakers/set the crossover? Do I need a receiver? (I decided I'm going to get JBL LSR305s)
Some powered monitors have 80hz high pass filters that can work as well where you then just set your sub high pass filter to 80hz; many don't in your budget range."
----I ended up deciding to get the JBL LSR305s. How can I look up if these are sufficient to do that?
Finally, in order to hook them up to my sub, do I need a receiver or can I just hook them up to the sub and the sub acts as a receiver?
Sorry for all the questions, I'm extremely new to this. Here are some pictures that might help:
This image is almost identical to the back of the PolkAudio woofer, except the low pass only goes down to 80 and the peak says 200 (I have no idea what that means unless thats the crossover point). Also above the red and white line in holes there is also a yellow one above it. Finally, the two pronged plug in on the right actually looks more like the 3 pronged plug on the jbl speakers (except there is only 2 prongs instead of 3). The other image is of the LSR305's rear panel.