Most loudspeakers have two or more loudspeaker drivers. For example, a woofer, a midrange, and a tweeter. The audio signal needs to be split into different frequency bands for each driver. In a loudspeaker with a passive crossover, this is done with passive components – coils, capacitors, and resistors – which are inefficient and can be expensive. In an active crossover, the signal is split into different frequency bands before any power amplifier. DSP-based crossovers like those that can be implemented with miniDSP are the most powerful of this type. Separate power amplifiers are then used on each loudspeaker driver, resulting in optimum damping factor and lowest distortion.