Intelligability Problem

On all 3 front channels?
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Do you have the Denon connected via HDMI? to your players?
The problem is in the Denon, almost certainly the Denon. It may be something as simple as some settings you currently are using in the Denon receiver are not good for speech, Perhaps some special surround mode? Or, perhaps you have the Denon set to decode a type of sound that is not exactly to the one being set, so it is messing up the decoding.
I have a Denon 4806 receiver, and can safely say it is WAY too complicated.

Thanks for the replies. I find that music and background sound is very good indeed. I am letting the BluRay player decode and am using the 5 analogue outputs to the Denon which is in ext. mode...meaning it is acting as 5 separate basic amps with a volume control. Speech coming from the center channel sounds totally muffled and sounds as though its from a 39cent speaker, although the NHT supposed to match the other speakers in sound quality. I am using HDMI directly from the Panasonic to the Sony hidef for video only, since my Denon has no provision for HDMI. I have adjusted the Panasonic to recognize that only video is HDMI. Any suggestions?

oops...to answer jeffreybehr... 5 channel NHT speakers all.