WTF is a Crossover?

Although audio system are vital parts in an audio system, many shoppers take them without any consideration. After all, aren’t they simply containers the place somebody has thrown in two or three speaker drivers they usually simply work?  They is likely to be, for those who purchased them from somebody promoting audio system out of the again of their van, however in order for you audio system that truly sound good, you want one thing that not solely appears good on the surface however is well-engineered on the within. 

For audio system that embody a tweeter and woofer, or tweeter, midrange, and woofer, a crossover is an integral element of the speaker in order that the woofer, midrange, and tweeter reproduce the frequencies that they’re optimized for.  

Crossovers For Audio Defined 

The time period crossover has two meanings in audio;

1. Some extent the place sure frequencies are divided (filtered) in order that they’re despatched to the speaker driver(s)  greatest designed to breed the directed frequencies.  

2. The circuit that truly divides (filters) the frequencies.

Types of Crossover Filters 

Crossovers incorporate three forms of filters.

1. High-Pass Filter (HPF): The frequencies above a delegated crossover level are handed via. 

2. Low-Pass Filter (LPF): The frequencies under a designation crossover level are handed via. 

3. Band-Pass Filter (BPF): This filter discards frequencies above and under particular factors and solely passes a band of frequencies in between these factors.

Additional Crossover Functions

Cutoff Frequency: This is the purpose the place the HPF, LPF, and BPF(s) frequency level(s) begins. It is necessary that this level is precisely positioned in relation to a speaker driver’s frequency vary capabilities.

Slope: This is the speed of frequency drop-off related to the cutoff frequency. The drop-off might be steep or gradual. The purpose that slope is necessary is that sound must mix effectively in order that there isn’t a noticeable abrupt swap between speaker drivers. 

Even although there could also be two or three speaker drivers assigned to deal with particular frequency ranges, the transition between them must be invisible to the listener. This means that there’s a slender frequency vary overlap between speaker drivers the place they’re reproducing the identical frequencies because the crossover arms over the designated frequencies from one speaker driver to a different inside a speaker meeting. This can also be necessary when matching an exterior subwoofer with the remainder of the audio system in a system. 

Tip: Sometimes, the crossover setting on a Subwoofer could also be labeled Low-Pass.

Types of Crossover Circuits

To carry out the filtering job there are two forms of crossover circuits: 

1. Passive Crossover: A Passive Crossover is a mixture of resistors, capacitors, and inductors, which might be set to divide frequencies at a selected level. No energy supply is required.

2. Active Crossover: An lively crossover makes use of a DSP (Digital Sound Processing) chip or Microprocessor to divide frequencies. A digital crossover accepts a full-range sign after which splits it into the low, mid, and excessive frequencies utilizing its DSP perform. In addition, an lively/digital crossover might embody adjustability. This choice is especially included in powered audio system, subwoofers, and AV receivers. As such, Active Crossovers require energy to work.  

Crossovers: Subwoofers and AV Receivers

The Crossover settings in an AV receiver are sometimes called Bass Management settings. Adjustable crossover/bass administration settings in subwoofers and AV receivers permit for extra exact crossover factors when utilizing subwoofers and audio system with completely different frequency vary profiles in a house theater audio system.

Crossovers in 2-Way and 3-Way Speakers

• A two-way speaker incorporates a woofer and a tweeter.

• A 3-way speaker incorporates a woofer, midrange, and tweeter.

In a 2-way speaker, the crossover is ready at a selected frequency level. Any frequencies above that time are despatched to the tweeter, whereas the rest is shipped to the woofer.

In a 3-way speaker, a crossover might be designed in order that it has two frequency factors—one for the purpose between the woofer and midrange, and one other for the purpose between the mid-range and tweeter. 

Tip: The frequency factors of the crossover range relying on the speaker drivers used and the speaker maker. 

For instance, a 2-way crossover level is likely to be 2kHz. This signifies that frequencies above that time are channels to the tweeter whereas frequencies under that time are directed to the woofer. 

In a 3-way speaker, there is likely to be a 200Hz level between the woofer and mid-range, after which a 3kHz level between the mid-range and tweeter.

Tip: The above illustrates the fundamental perform and building of crossovers, however many speaker makers add their very own “twist” in using building supplies, variety of parts within the crossover (order),  and for digital crossovers, DSP, and adjustment vary. 

Related Reading

WTF is a Subwoofer?

WTF is LFE (Low-Frequency Effects)?

Don’t Hookup Your Subwoofer Until You Read This

Basics of Bass: The Strange and Confusing World of “Bass Management”

Receiver and Subwoofer Crossover Setup

WTF is Impedance?