The Maxx BCL is a serious piece of hardware. Two rack spaces and it’s hefty — some of my power amps weigh less. The short version is that the BCL combines the MaxxBass system with a compressor and limiter. The idea is more low end and total signal level without increasing distortion. Bottom line is a louder mix with at least the perception of more bass. According to Waves, the guys mixing acts including Gwen Stefani and Metal-lica are using them as part of their system.