What are the differences between this model and the S-DJX Series/RM Series?

1. This model differs from the RM Series that seeks to give accurate sound positioning, instead offering the combination of balanced sound and rich bass sought by hobbyist DJs and producers.
2. 4-inch speakers that are more compact that those used in the RM and S-DJX Series.
3. Sold in pairs, unlike the RM and S-DJX Series, which are sold as single unit.