Put simply, audio distortion is to some extend present everywhere around us and our best hope is to minimize it such that our brain doesn't notice it.  When it comes to audio and loudspeakers, let's make clear that there isn't such thing as a "distortion free" loudspeaker.

So where does the distortion comes from?

Many places within the audio chain may be responsible, and most likely the loudspeaker will be a strong contributor. Because of mechanical and acoustic limitations, loudspeaker drivers simply cannot reproduce a wide range of frequencies without distortion.

Crossovers to the rescue!

Coming to the rescue are crossovers, a set of filters used to separate frequency range for a specific loudspeaker driver, e.g. a subwoofer optimized for a  frequency range from say 20 to 150Hz will need a crossover to limit the bandwidth of the signal being fed to the cabinet.

Passive versus Active?

Passive crossovers apply to electronic filters that do not require external power supplies (passive electronic). In their basic essence,  coils and capacitors perform the task of filtering the audio signal after amplification and separating the frequencies to the correct driver. They are the most common crossovers out there, as they are low cost to manufacture and handy since you only need a single amplifier channel per loudspeaker. The real downside is their lack of efficiency and how the components will affect the flatness of the frequency reponse. This disadvantage causes considerable grief to loudspeaker designers, battling to improve low to medium overall acoustic performance.

Active crossovers, on the other hand, require an external power supply and will separate the signal before amplification. They, therefore, require one amplifier channel per loudspeaker network. (e.g. Low/Mid/High will require 3 amp channels). No more impedance loading interaction from the passive networks, what you design is what you get! Time alignment couldn't be easier and with cost of amplification coming down, active crossovers are winning hands down over passive crossovers. Try one our miniDSP kits to hear the difference!

For more information about digital crossovers, follow this link.