I just bought one of these a few months back for an electronic music night that I promote. We were just running two MSR400s and to be quite honest, it sounded great. As the night started gaining traction and filling with people I realized that a couple of top boxes would not cut it anymore so I bought this sub. I run DJs and live electronic musicians through this for five hours a night and it delivers. The lows from this sub perfectly balance the mids and highs coming from the MSR400s. I would recommend buying this sub if you are only running powered top boxes, you will thank yourself and so will your audience.