Help with Gym Speaker Setup.

Hey guys, I have an old Yamaha StagePas 500, with the amp and the pair of speakers. I’m using them as my home gym speakers. I’ve noticed the lows are pretty pathetic, and I’d love to add a sub to accompany them.

Can the amp handle this? If so, would you guys recommend a specific sub? Im not an audio guy by any means and I don’t want to blow my amp or ruin equipment.

Also, sorry if this isn’t the correct sub for this question. I can’t find the correct sub to post in, and I know you guys are very speaker savvy