When I didn't have any subs I used a pair of double 15's to make up for that. The Yamaha S215's I have kick major butt still. They are way better then the KBL JRX 125's I used to have. They sounded OK. They just couldn't take any real power. I blew several crossovers and tweeters using them. I've never had an issue with the Yamahas.