The allegro was never designed to "go DEEP" with regard to bass. It was FISHER's attempt at a portable system to counter some of the units from other manufacturers such as the KLH 11 or 12. It does good for what it is, a low powered phono or AM/FM phono portable. You will in all probability have to go with a powered sub that branches off the speakers from it. But if it were mine, I'd leave it as is, and do some old fashioned human virtual reality on the bass (close your eyes and use your imagination.)