When using a receiver for your TV sound aren't you suppose to mute the volume on the TV ? Are you guys muting your TV sound when using a receiver ? I'm telling my wife that using the TV speakers for sound plus the receiver/speakers is not a good ideal and it defeats the purpose ? She ask why but I don't the answer exactly.
I currently have a kinda crappy 2.0 channel right now and she is right about one thing for some reason when I do use the TV speakers with my receiver/speakers it does seem to sound more full, the mid-range and the high-range really do seem to come through better when making comparisons when switching back and fourth while watching TV. I'm telling her it's not normal that the sound is better with TV & receiver/speakers. I've played around with settings but it makes no diff, it does sound better when I don't mute the TV. thanks
The short answer is that there is no "right way" to do this. So, do whatever sounds best TO YOU.
Personally, the speakers in my TV are shut off in the TV menu, not used at all and I have 5.1 speakers.
If you only have a (crappy) 2.0 or 2.1 system, then it may indeed make sense that it sounds better with the TV speakers going too. For a true 5 channel setup, I would say shut the TV speakers off. The center channel should be located just above or just below the TV, and if the TV speakers are going too, then you will most likely get constructive/destructive interference and it will sound bad.
If you have a GOOD 2 channel system, then it can be very convincing using a "ghost center". What this means is that if your L/R speakers image very well, then you don't need a center channel at all as it will fool you into thinking that the sound is coming from the TV. For example, my GE Triton IIs sound very good without a center. My GF didn't believe that my center channel wasn't even playing anything.
The bottom line, try it both ways and go with what sounds best. Why would you do something if it made your system sound worse?
Now, if I were you......I would use this as an opportunity to leverage the spouse into giving you permission to upgrade to a quality audio setup and then turn off the TV internal speakers.