Does a center channel have to match the front spke

You would be better off with matching center channel speaker. Their will be things that will pass from left to right or right to left and will travel thru the center speaker. If they do not match fairly close, you will hear the tone change as it sound leaves the outside speaker, passes thru the center channel, then change back as it enters back thru the opposite outside speaker. Of course, if you find a dealer that will let you demo a non matching center speaker, try it and see. You just might get lucky!

the center may not have to be an exact match for your mains, but you're better off if it's a close match. If Dynaudio has a budget center - not necessarily the same speaker elements but having the "house sound" it will probably work. When I first started to assemble my HT, I tried a couple of center speakers that were decent, but not the same brand - it was awful. I now use the entry model center speaker in the same brand as my mains (which aren't entry) and it works nicely.

Good question!
For proper film, center is for dialogue only-so that leads one to believe you could use a different speaker successfully. Music/effects are NOT sent to the center. However, there are some newer mixes that defy this and who knows what future mixers might do? So this sort of says "the only safe bet for the future" is all speakers the same. In my own case, I cannot do the same so I use (the same brand center) that is voiced the same as my L/R/SR/SL. Less low end in it (fine for dialogue) but sounds very much like the mains. I spent more than I thought I would for the center but all other lesser options sounded too different. I am glad I did, sounds really nice now.

For music, different story completely. Music mixers DO use the center for music, they can sort of do anything they want, so this means all speakers must be the same, rear channels, center, fronts.
Brad

I have been using a Kef 204c center channel with Revel Studio, Verity Audio parsifal and Avalon eidolon respectively, and I have always been very pleased with the result. However, ever susceptible to the "upgrade" itch I started looking around for a better match for the Eidolon's. Considering Avalon does not make its own high end center, (and if they did it would be prohibitively expensive), I ordered the Salk Soundscape center, which has the same accuton midrange driver. It will be arriving tuesday. During my search I came across a company call Selah, who will custom build a center with the driver you want to match. I believe he will charge you around $2500 and use the esoteric tweeter and matching midrange. Worth considering.

This is so often a snobs arguement. So many speaker use a box, a port, off the shelf drivers so how much at odds would sound be between similar makes and sizes? Could 90% pick a well matched non matching center with a blindfold? Could 50%? Could 20%?
Then you have those who have a "matched" center, yeah its from same company but the drivers arent even identical...huh?
The point is far, FAR more speakers that dont match makers or even drivers can and will work just fine, I have 3 surround systems with 1 correctly matched and 2 not matched but carefully selected, well 1 was lol,if anyone wants to come down and take my challenge I will film it and post on youtube.
Buy what you can or what you want, it will in almost ALL cases within reason work just fine.