I'd definitely experiment with different sub positions and angles, and the crossover/volume settings on the X30 before getting another sub.
I have an old NHT SW3P being powered by a Bryston 4b, controlled by a Paradigm X30 and have achieved satisfying bass for my small room. Opting for a lower crossover setting helped reduce boom and give the illusion of better speed and pitch. And, finding an unorthodox location mid way along the side wall facing in helped too. It can take a lot of work and listening, but the results may surprise you.
Two smaller, faster subs might be a better solution. That is if you can swing the extra cash and have the room for them.
I have an old NHT SW3P being powered by a Bryston 4b, controlled by a Paradigm X30 and have achieved satisfying bass for my small room. Opting for a lower crossover setting helped reduce boom and give the illusion of better speed and pitch. And, finding an unorthodox location mid way along the side wall facing in helped too. It can take a lot of work and listening, but the results may surprise you.
Two smaller, faster subs might be a better solution. That is if you can swing the extra cash and have the room for them.