Assuming it's an 8 ohm cab add an 8 ohm 2x10 on top. A 15 is never going to get you the definition of 10's...
It's not just that it's 1x15" - this is a Kustom 1x15". Not a Berg, or an Aggie - a Kustom.
So yes - you want to sound more "articulate"? Better cab. Save your $$ and get something nice.