I bought this for my subwoofer speaker columns lacked serious, especially at low volume. This subwoofer is very good, the bass is sharp and detailed. You can adjust the amount of bass for his taste and the cutoff frequency regulator (crossover) to properly balance the bass of the box with the speakers. We need to experiment with different types of music. I have a Sony amp and before I had the bass settings almost always at maximum. Now it is more balanced and I have the margin. It is a 4-channel amp, so I plugged my subwoofer on the second system. Only weaknesses is that the settings are the back of the box. A front adjustment (with cache) would have been more convenient. Second weak point is that the bass speaker is under the box without any protection (eg grid). So be careful when lifting the subwoofer if one puts his hands underneath.
Otherwise it is a perfect box for me with my two tower speakers JBL Loft 20.