You can add a single speaker to the cart right on the web page when browsing the different speakers.

Also, consider the 3 M22's across the front as John stated. Not only will it save you money but it will create a better front sound stage. That's a win win as long as your room configuration can accommodate the vertical center. cool

Dan
On-Wall M5HP LCR, QS8 & EP500 in 7.1