Should you trade in your unpowered monitors for powered ones? Well, the perception of sound is a rather subjective experience, so powered monitors might not be everyone's cup of tea. After all, many accomplished engineers are extremely comfortable mixing on Yamaha NS-10Ms, whereas others cannot abide that monitor's accentuated midrange. Though you might be in a blissful relationship with a favored unpowered monitor, here's what you'll gain if you do decide to “plug in.”
One advantage a good powered system offers is unity of design. Subtleties of cabinet design, crossover frequency, equalization, and every other factor known to science can be taken into account during the design stage of the system, and components can be selected that complement one another. For example, power amps can be exactly calibrated to specific drivers, and onboard equalization can be applied to flatten out and extend the system's frequency response. In an unpowered system, your power amp may not be a good match for your speakers; a powered system, on the other hand, ensures absolute harmony between the amps and drivers.
In addition, most powered monitors let you contour the speaker to your listening environment. Onboard frequency controls let you “goose” the high end or roll off the bass to match the idiosyncrasies of your room. Or, if you travel from place to place, you can tune the system to any number of different listening environments. All of this precise control over system design often translates into a superb, matched reference system that delivers exquisite frequency response, low distortion, and articulate stereo imaging.