It's possible, but I really would not recommend it. The different and probably very bad sound of your tv will _destroy_ the soundfield. A center speakers is not highly important. It would be better to not have a center than to have a very bad center. You can always redirect center sounds to the mains.
I hope Landroval's statement "center..not highly important" was a misprint and I am sure he knows better as in any home theater the center is the single most important speaker in the bunch. Using a tv speaker is a terrible idea and you should be buying a matching Klipsch center before, not after a sub.
I'm a center speaker fan myself, but I've also heard many 4.1 setups with no center, and they work quite well if the front speakers are correctly placed and you sit close to the sweet-spot. The two fronts are very capable to produce the sounds that should come from the center.
Everybody, try your systems with no center speaker, just turn it off from the receiver. Play a multi-ch movie while sitting in the sweet spot. Then do the same thing for the sub.
I bet most wont even notice the absence of the center, but very easily the sub.
A no-center speaker set up will perform just as well especially if only two or three persons listening or watching the movie. Just tilt the right speaker pointing directly to the leftmost person and the left speaker directly to the rightmost person. This arrangement will give a soundstage as if you have a center speaker, even if youre sitting off center. For movies, its better to have no center speaker than no subwoofer.
"Everybody, try your systems with no center speaker, just turn it off from the receiver. Play a multi-ch movie while sitting in the sweet spot. Then do the same thing for the sub.
I bet most wont even notice the absence of the center, but very easily the sub."
I had this for a month while waiting for my centre and you don't notice it.... Unless there's dialogue of course, then you may miss entire conversations and have to turn on subtitles. For action it definitely adds quite a bit, but could be lived without. But why live without?
I once had the center channel unhooked because the wire came loose, i noticed something sound different but the movie still had the sound effect it supposed to have. I just had to mess with the volume because the music was to loud and the talking was to low, but to miss the special effects from a sub i would diffently miss that.