I have owned a Cube Bass 100 for over 8 years, I added extra porting to the rear to extend the internal speaker low end and added a parallel 2 xjack socket plate. I can run the internal speaker in parallel with an extension cab or just an external cab on it's own. The amp comfortably drives the two 8 ohm speakers at 4 ohms without any fuss or bother.Great flexibility for home or small pub venues.