Acoustic crossovers are electronic devices that take one input signal and produce two or three outputs consisting of separated high, mid and low frequency bands. Different ranges feed different speakers or "drivers" in a sound system: woofers and subwoofers. Without a crossover, a random breakdown of sound occurs. In these, a high-pass filter blocks lows but sends high-frequency notes to the tweeter, while a low-pass filter blocks highs and passes low-frequency notes to the subwoofer.
Component sound system
Crossover "networks" of coaxial multi-range car speakers are usually built into speakers and consist of small electrical components such as coils or capacitors. Crossovers for three-way systems using tweeters, midrange drivers, and subwoofers include, in addition to high and low pass filters,"bandwidths" reproduce frequencies between two points using both high and low frequencies on the same network. For this, there may be a mid-range driver only from 100 Hz to 2500 Hz.
There are two main types of acoustic crossovers: active and passive. Passive ones do not need power to filter the signal. Active ones require a power and ground connection, but give you much more flexibility and precise control over user music.
Active audio system
A sound system is called "active" when each driver, tweeter, subwoofer has its own amplification channel. This greatly increases the available power, dynamic range and control of the system's tonal response across the entire audio spectrum. An acoustic active crossover connects between the receiver and amplifier and cuts off unwanted frequencies so it can only focus on the frequencies the user wants to hear.
They usually have volume controls on each channel, so you can keep all the "voices" from different drivers in balance. Some crossovers include other audio processing features such as equalization to further customize the system. The only potential downside to this kind of crossover is that it requires +12V, ground, and plug-in connections. This presents a bigger problem to install and configure than a passive device.
Passive acoustic devices
Acoustic passive crossover is not connected to a power source. There are two types of passive crossovers: component crossovers, which are connected between the amplifier and speakers, and built-in ones, which are located between the receiver and amplifier.
Component. The passive transitions of the components in the signal path come after the amplifier. These are small networks of capacitors and coils that are usually installed near loudspeakers. Component speakers come with crossovers set for optimal performance. They are easy to install and configure. The full range signal exits the amplifier and goes to a passive crossover which splits it in two and sends the high notes to the tweeter and the mids and lows to the woofer. Most passive component crossovers have additional settings that allow you to turn off the tweeter if the sound seems too loud for the woofer.
In addition to passive crossovers that operate on loudspeaker signals and are connected between the amplifier and speaker components, there are also built-in acoustic car crossovers installed in front of the amplifier. They look like little cylinders with RCA plugs on each end and simply plug into the inputs. Built-in crossovers do not waste energy like high frequencies do for a subwoofer. Installing a built-in crossover is a great and inexpensive way to improve the sound of the center, especially in a component speaker system.
Principles of using car audio
To understand what a crossover is and whether the need for sound really needs one or more crossovers, it is important to first understand some very simple principles for using a car crossover. The main idea is that music is made up of sound frequencies that govern the entire gamut of human hearing, but individual sources are better at creating specific frequencies than others.
Tweeters are designed to reproduce high frequencies, woofers are designed to reproduce low frequencies, etc. The main purpose is to separate music into its component frequencies and send it to specific speakers to achieve higher audio fidelity. By making sure that only the right frequencies reach your classic speakers, you can more effectively reduce distortion and improve the sound quality of your car audio system.
Installing passive acoustic crossovers is a relatively easy task as it provides crossover wiring between the amplifier and speakers. For example, you could connect a passive crossover to an amplifier output, then connect the tweeter output to a tweeter and the subwoofer output to a subwoofer.
Installation of an active car audio crossover will generally be a more complicated procedure. The main problem is that active crossovers require power, so you will need to run power and ground wires for each device. If already installedamplifier, it will be easier to install an active crossover. In fact, grounding it in the same place as the amplifier is grounded will help prevent annoying noise in the ground loop.
Crossover Classification
Acoustic crossovers can be classified by the number of bands into which the audio spectrum is divided. The two-way splits the audio spectrum into two parts and sends the information to different types of drivers. Three-way divides the audio spectrum into three parts, and so on. A crossover can also be described by the point where the steep cut begins. It usually refers to the frequency at which the descent starts. In duplex, both drivers will have 6 dB at the crossover point.
Terms often used to describe crossover slope include 6 dB/octave, 12 dB/octave, 18 dB/octave, or 24 dB/octave. The slope of the crossover that these terms refer to. For one octave change, a 6dB/octave crossover will have an output that is 6dB below the starting point; 12 dB/octave will have a 12 dB output. Another set of terms that are often used to describe crossover slope are 1st order, 2nd order, 3rd order, and 4th order.
These terms are derived from the number of components needed to create the slope described. A 1st order crossover uses 1 component and will give approximately 6 dB/octave. A 2nd order crossover uses 2 components and will give you about 12 dB/octave, etc.
Center speaker components
If it is difficult to find a value that is no more than 10% of the desired sound, adjust. Heresome tips for working with different components:
- Capacitors: combine two capacitors, connect them in parallel. Using them in this way, one can simply add the two values together to get the combined equivalent capacity.
- Resistors: connect two resistors in series to provide a combined resistance equivalent to the total value. The power rating on both must be high to meet system requirements.
- Inductors: If you don't need to use multiple inductors, you can buy an oversized one and then unwind the coils until the desired value is reached. The disadvantage of this method is that you must use a specific type of inductance meter.
Define frequency range
Adjusting the crossover of the speaker system is the correct frequency adjustment. To determine the allowable range that is used for settings, you need to know the data for both the speakers and the subwoofer. The purchased speaker package always contains a guide for the settings you need to use.
Otherwise, the following rules apply. The highest frequency the subwoofer can handle should be used for crossover settings. The lowest frequency that the speaker can handle should be set to crossover.
For example, for a subwoofer frequency range of 20-130Hz and a center speaker frequency range of 70-20,000Hz, the allowable rangeThe crossover setting for the main speaker will be 70-130 Hz. This means you can apply a setting of 70, 80, 90, etc., up to 130 Hz for the main speaker. If used above or below the specified size, then frequencies outside the limits will not be reproduced by either the subwoofer or the corresponding speaker.
Main building blocks
In a car audio system, large outboard capacitors are used to prevent the lights from fading when loud bass notes are played. They achieve this by giving the amplifier a quick burst of power. Speaker crossover capacitors have a high "resistance" commonly referred to as reactive for low frequency signals.
There are three main specifications for capacitors:
- The maximum voltage at which it is not subject to dialectical breakdown. This breakdown occurs when the electric field between the two plates of the capacitor becomes sufficient to polarize the dialectic, thereby turning it into a conductor. When this happens, the capacitor will become hot and may explode.
- The capacitance of capacitors is usually measured in microfarads - mF or uF or (Greek letter mu) F. A microfarad is 1/1,000,000 or 1 × 10 -6 Farad. And Picofarads are also used, which is 1/1,000,000 or 1 × 10-6 microfarad (1 × 10-12 Farad).
- Tolerance. This is an acceptable variation of the value. For example, a 47mF capacitor with a range of -20%/+80% would behave a capacity from 37.6 to 84.6 mF. Audio systems typically connect a capacitor in series with each "high-frequency" speaker to act as a high-pass filter.
Calculate system impedance
If all speakers are connected in parallel and have the same impedance, then acoustic crossover calculation is easy to do. Simply divide the impedance by the number of speakers in parallel.
Example 1: Four 8 ohm speakers, parallel connection: 8 / 4=2 ohms. Example 2: Two 4 ohm speakers, parallel circuit: 4 / 2=2 ohms.
To calculate speakers connected in parallel but having different impedances, the following formula applies:
R total=1/(1/r1+1/r2+…..).
In fact, the exact calculation of the audio system is a very complex empirical process. To make it easier, there are many online calculators for speaker crossover on the internet, such as a separate calculator for 2, 3, and 4 speakers connected in parallel, as well as calculators that can be used for more complex series/parallel configurations. To do this, you need to enter the impedance of each speaker in the white squares of the corresponding calculator. The total impedance for speakers connected in parallel will be determined. And also a percentage is calculated for each speaker.
The display will show how the output power of the amplifier is distributed between the speakers. When used together with different impedancepower sharing will be taken into account.
If there was one driver that could easily and accurately reproduce the entire spectrum of audio, there would be no need to use a crossover. The main reason is that multiple drivers are usually required to cover the full spectrum of sound. It is not possible to make a driver capable of producing both high and low frequencies at the same time. Different types of drivers are designed to work well in different ranges. Using a crossover helps to coordinate the work of different drivers.
