Active vs Passive Crossover

The crossover is an electronic device that functions to take a single input signal and split it into two or three output signals that are separated according to the frequency range: high, mid, or low frequencies. These different bands of frequencies are fed into different speakers or drivers, which are the tweeters, woofers, and subwoofers. Without a crossover, a messy sonic traffic jam results: the woofers and subwoofers will duplicate many same frequencies, and they may also try to put out high notes they aren’t meant to handle. Meanwhile, the delicate tweeters can get destroyed when trying to produce thumping bass notes. So, a crossover is an essential part to any speaker or sound system.

In general, crossovers can be classified into two basic groups, active and passive. Below, we will see the differences and comparisons between active and passive crossovers. Continue reading!

What is a Crossover?

You can find audio crossovers in various loudspeaker cabinets, power amplifiers, car audio systems, and pro audio systems. An audio crossover is an electronic filter circuitry that is used in various audio applications to split a single input audio signal into two or three frequency ranges. So, there are two-way and three-way crossovers; a two-way crossover splits the signal into high and low frequencies (the midrange and bass frequencies are usually combined into one channel), whereas a three-way crossover splits the signal into high, mid, and low frequencies. Audio crossovers are used because individual drivers are not able to cover the entire frequency range from the lowest to the highest – not without distortion and loss of volume. So, a crossover is used to ensure that each specific driver in the audio system can focus on processing a particular frequency range with optimum performance.

Active Crossover

In short, an active crossover is the one that requires power and ground connections, but is able to give you much more flexibility and control. An active crossover is wired between the receiver and the amplifier, allowing itself to cut out unwanted frequencies before the amp wastes power boosting them so that the amp focuses on just the frequencies that you want to hear. An active crossover usually has volume controls for all the channels so that you can configure the balance of all the drivers. Some advanced models may include additional sound processing capabilities, such as equalization features.

However, an active crossover would require +12V, ground, and turn-on connections. Thus, it serves more challenge to install and configure if compared to a passive crossover. However, with some time and care, the rewards are great. That’s why active crossovers can be found on virtually any competition-level car audio system as well as any high-end home theater system.

Passive Crossover

On the other hand, a passive crossover is the one that does not need a power source to work. Passive crossovers can be grouped into two types, which are component crossovers and in-line crossovers, so let’s see first the differences between the two:
– A component crossover is a crossover that steps into the signal path after the amplifier. It is made of a small network of coils and capacitors, and functions to separate the signal after the amplification. It usually comes with the speaker system set up for the optimum performance. However, a passive crossover may release unwanted parts of the already amplified signal as heat. Also, since speakers change their impedances when playing, a passive crossover’s crossover point (a.k.a. frequency response) may also change during the operation, leading to inconsistent sound definition.
– An in-line crossover connects right before the amplifier. It looks like a little cylinder with RCA connectors. However, an in-line crossover is set to a specific frequency and thus can’t be adjusted. In addition, in-line crossovers react differently to different amps, possibly changing the crossover points unpredictably.

Advantages and Disadvantages of a Passive Crossover

The obvious advantage of using a passive crossover is the plug-and-play simplicity. It is much easier to set up and configure. It does not need any power or ground.

However, a passive crossover has several disadvantages. Most of these disadvantages are related to the output quality. As mentioned above, a passive crossover’s crossover point may change during the operation, thus producing inconsistent sound definition. In addition, a passive crossover also causes more interference to the input signal, compromising the output sound quality. It causes the loss of damping (the ability of an amp to control the motion of the speaker once the signal has stopped) and reduces your control over the sound. And a passive crossover would leave the amp alone to deal with the combined complexity of power draw and impedance load – high power draw in a specific frequency range (usually the bass) may lead to clipping on the amp and damage on the drivers.

Advantages and Disadvantages of an Active Crossover

Obviously, an active crossover requires a more complicated setup, with more amps and cables. An active crossover is more susceptible to electromagnetic and radio interferences, thus requiring careful placement to put it away from electromagnetic and radio signals. In addition, an active crossover may produce more noise, though this issue can be easily solved with a digital processor.

However, an active crossover would give you direct control over each of the drivers. It ensures that each amp only deals with a specific frequency range, reducing harmonic and intermodulation distortions for the best sound quality. It is indeed more efficient, in the sense that the amp does not need to spend power to amplify unwanted frequencies. It also ensures an easier impedance load on the amp, eliminates power loss or damping factor, and reduces clipping.

Active CrossoverPassive Crossover
- Installed between the receiver and the amplifier- Can be installed after the amp (component crossover) or right before the amp (in-line crossover)
- Requires power and ground connections, relatively more difficult to install- Does not need any power or ground connection, much easier to install
- Good power efficiency- Bad power efficiency
- Allows extensive control over the drivers- Little to no control over the drivers
- Better sound quality- Lower, inconsistent sound quality

Conclusion

An active crossover is a crossover that is installed between the receiver and the amplifier. It can filter the input signal before it is amplified. It requires power and ground connections. It requires a more complex setup, but gives better control, performance, and sound quality. Meanwhile, a passive crossover is set with a specific frequency and is much easier to install, but offers reduced control and sound quality.

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