Ontherock, Bob Fields is telling me I have the C3(pictured in the post) can't say for the C5, seeing I don't have one but the dimensions of the C3 are: Measuring the grill 4 1/4" wide, 5" long and its 2" thick, the speaker itself is 3" dia. Don't know this for sure but I assume 3"=C3, 5"=C5???? If you were to upgrade I would like to purchase one of the speakers, if you want to sell and if you now have the C3's. Like I said in a earlier post you can get the C5's on Ebay for $10.00 ea. plus about $8.00 shipping. There's a pic of the C5 with the ad. Hope this helps.