Active vs Passive
Active (powered): Built-in amplifiers, one per driver. Individually amplified, optimized crossover. This is what you want — 99% of studio monitors are active. Just plug in power and your audio interface.
Passive: Need a separate amplifier. Mostly high-end installations. Not recommended for home studios.
Driver Size
5" woofer: Nearfield, small rooms. Clean mids, rolled-off bass. Pair with a sub or headphones to check low end. Good for apartments.
6.5-7" woofer: Sweet spot for home studios. Enough bass to mix without a sub in a treated room.
8" woofer: Full-range in a medium room. Can overwhelm small untreated rooms with bass buildup.
Room Matters
Even $2,000 monitors will lie to you in an untreated room. Bass traps in corners and absorption at first reflection points (side walls, ceiling) make a bigger difference than upgrading monitors. Start with monitors you can afford, spend the rest on treatment.
Brand Tiers
Budget ($150-300/pair used): KRK Rokit, Yamaha HS5, JBL 305P. All excellent, just different flavors. KRK = bass-heavy (check mixes elsewhere), Yamaha = mid-forward (vocal clarity), JBL = most neutral at this price.
Mid-Range ($400-800/pair used): Adam T7V/A7X, Focal Alpha, Neumann KH 80. Ribbon tweeters (Adam) for detail, Focal for punch, Neumann for accuracy.
Premium ($1000+/pair): Genelec 8000 series, Neumann KH 120/310, ATC. The reference standard.