Originally Posted by invenetix
So I bought a Denon DHT-391XP [...] I got my system setup today and was surprised to find that the sound quality in the midrange area seems... muddy. The 391 only has the ability to adjust the treble and bass only. It seems to me like the midrange is higher than it should be out of the box. [...] I'm running my system in a 3.1 setup
The midrange is both too loud and muddy? You can turn up both the bass and the treble to get it to the same loudness as the midrange. The muddiness might be due to your subwoofer's location or volume or both, but that's just a guess.
Have you put the receiver in direct mode and listened to a two-channel source such as a CD or a MP3?
Also, you could try connecting the surround speakers, even if you don't have a proper place to put them.
I have to say, though, that the unit you have is advertised as "entry level". Are you sure that you'll be happy at that level? If you upgrade from the 391 to the 591 you get a huge boost in the capability to equalize things like a midrange that's too bright. In fact, it makes the adjustment for you automatically. Of course, if the speakers themselves are "entry level" I'm not sure that any amount of equalization will make them sound good to you.
What sounds bad to you might not sound bad to others. Did you tell your friends your opinion of the audio quality before you asked them theirs?
Also, speaker placement is important. My son-in-law bought a 3.1 Bose system, and said he was disappointed in the way it sounded. He said it sounded a lot better when he heard it in the store. I was staying with them when he told me this. I suggested that the difference is due to speaker placement. I moved them around a bit, and thought they sounded better. Then, the next day, he moved them back to where he'd originally had them!