You should add Formula Sound (UK) [based in Cheshire] to the pro quality & install categories for DJ mixers: high quality analogue units with different configurations depending on model. I use a PM90 (previous model to their current PM100) with external PSU and top quality circuitry. I have no affiliations with the company. Decks.co.uk i.e. Sapphires list the Formula Sound FF6000 "The features and layout of the FF-6000 were determined in collaboration with leading loudspeaker manufacturers Funktion One, who canvassed many DJs world wide on their requirements". For DJ studio monitoring add Quested Speakers (Roger Quested) and ATC monitors. Both Studio grade excellence that can take extended professional SP levels and provide outstanding insight into the mix. Add Sennheisser to pro headphones (cans) for Sennheiser HD-25C-II Dual Band Headphone model. Mine have lasted 17 years daily use just with replaced headband pads and velour ear protectors.