Looking much like any other compact subwoofer box, the DSA 500RT is in fact a treasure chest full of surprises. Inside the box there is a 3-channel class D amplifier for subwoofer and front speakers and a multifunctional digital sound processor combining active crossover, equalizer, time alignment and dynamic compression systems. This unique solution from Focal provides an easy to install upgrade to any factory system. Just adding this single box will improve the performance of the entire system including low frequency response, dynamic range, tonal balance and imaging. Sometimes, big surprises come in small packages.