A crossover is a key element in the overall design of a multiple-driver system. It is designed to filter sound into frequency ranges the way a prism filters light into colors. There are two common types of crossovers, "passive" and "active". Both types of crossovers consist of a single (or group) of electronic parts responsible for dividing or "blocking" frequencies. Once the frequencies are divided or "blocked", they are routed to the correct speakers.
 |
| Passive Crossovers are non-powered components. They consist of capacitors (and/or) inductors placed in-line with the speaker leads located between the amplifier and the speaker. |
 |
| Active Crossovers are powered components. They are typically electronically powered "black boxes" placed in-line with the RCA signal cables located between the source unit and the amplifier(s). |
Crossovers Types There are three primary types of crossover filters: high-pass, low-pass, and band-pass. For special applications, there is a fourth filer called a infrasonic-filter.
 |
| High-Pass Crossovers allow high frequency information to be passed to the speaker while the low frequency information is attenuated in amplitude as the frequency decreases. |
 |
| Band-Pass Crossovers are the combination of high pass and low pass filters. Band pass filters assign a specific band of frequencies to pass through to the speaker. The most common use of a band pass filter is the mid-bass frequencies (100 Hz - 275 Hz). |
 |
| Low-Pass Crossovers allow low frequency information to be passed to the speaker while the high frequency information is attenuated in amplitude as the frequency increases. |
 |
Infrasonic Filters are high-pass crossovers centered around 25-30Hz. They are designed to block out subwoofer frequencies that are not useful in the automotive environment. This saves valuable amplifier power and improves woofer control. Benefits include:
|
Crossovers Slopes Crossover slopes are the amount of attenuation per octave from the crossover point in decibels. These attenuations are also referred by order of slope. An Octave is a doubling of frequency, from 50Hz to 100Hz would be considered one octave.
| 1st order: 6dB per octave 2nd order: 12 dB per octave 3rd order: 18 dB per octave 4th order: 24 dB per octave |  |
Crossover Point Selection
The first consideration when designing a crossover system is to address the most vulnerable of all speakers, the tweeter. Since tweeters have small, fragile voice coils, they can be over-driven very easily. Choose a tweeter that can begin reproducing frequencies where the midrange stops (avoid gaps in the tweeter-to-midrange transition.) Second, select a crossover frequency that allows the response of each driver to remain flat on either side of the crossover frequency. Try to select a crossover frequency at least one octave away from the speaker's resonant frequency. This is very important for tweeters because they can sound "harsh" if frequencies near the Fs (resonant frequency) are reproduced.
| Common Frequency Ranges | |||
| SUB BASS | MID BASS | MID RANGE | TREBLE |
| 20Hz-100Hz | 100Hz-250Hz | 250Hz-5kHz | 5kHz-20kHz |
 |
| 2-way Crossover Systems are typically used with tweeter / midrange combinations. In a 2-way speaker system, high frequencies go to the tweeter and low frequencies to the midrange. 2-Way Systems are great for people want good music reproduction and want to add a subwoofer in the future. You may notice most "component systems" already come supplied with a "ready-made" crossover. These 2-way crossovers are designed for the specific type of tweeter / midrange combination. Higher quality models usually have additional impedance compensation and attenuation networks that provide a "flatter" frequency response. * see below for graph explanations |
 |
| 3-way Crossover Systems are typically used with tweeter / midrange / woofer combinations. A 3-way crossover divides the signal into three different frequency bands: low-pass, bandpass, and high-pass. 3-Way Systems give the listener awesome sonic performance because of their ability to properly reproduce all frequencies in the human hearing range (20Hz to 20kHz.) One reason to use three speakers in a system is the appetite for more bass. You'll need larger diameter speakers (woofers) to move the large amounts of air required to reproduce low frequencies (i.e.: 20Hz to 80Hz.) * see below for graph explanations |
| ||||||||||
Was this article helpful?
That’s Great!
Thank you for your feedback
Sorry! We couldn't be helpful
Thank you for your feedback
Feedback sent
We appreciate your effort and will try to fix the article