Thanks for taking the time to post your question. I will see if I can help.
First things first. Take the time to go through the Automatic Setup of your Surround Sound. (Auto MCACC)
This procedure is described in detail on page 37 of your users manual, which can be found here. Doing so will ensure that your receiver is accurate for your room environment. You do not have to use these settings, but they can serve as a starting point. The AutoMCACC helped a lot in my media room and my Pioneer VSX-9120TXH, although I did do some minor tweaking after it completed.
After that check the gauge of speaker wire you are using. I personally wouldn't use anything less than 14 gauge (the lower the number the better). If your speaker wires look a little thin, I would suggest this cable from Monster Cable.
I hope that information helps, and I am sure some of the Home Theatre Experts will have a few things to add.
Please join the forum and let us know how it worked out for you
