Looking to upgrade my towers

Before you spend any money on new gear, you need to figure out what's wrong with your current system. It would also be a good idea to list a system you've heard, and would be happy with.

You'll never get good 2 channel sound quality running the signal through HT gear. If you have a source with a volume control, plug it directly into the amp and see how it sounds. If not, you can get a passive line stage. You don't have to spend a lot of money on one. That should do more for your current system than a new pair of speakers. If you buy new speakers, you'll just have the same problem.

You'll hear a big difference even if you get a cheap one. Of course you can spend more money and get one that sounds better, but the main thing is to get the HT processor out of the signal path. I have one made by Channel Island Audio that would be fine. It sells for $200-$300 if I remember correctly. Creek also makes a good one.

If you've ever wanted to try something like an AQ Dragonfly, that will work as well. It sells for $100 and you can use it with a computer, tablet or smart phone. You would run a cable from the DF directly to an input on your amp. Best Buy sells them, so can always return it if it doesn't work out.

You would treat the passive the same as any preamp. The line outs on the passive would go to 2 channels on your amp. If you need to use those channels with your HT setup, get a passive with more than 1 input and switch back and forth between the 2.