How To Install A Subwoofer And Amp In A Car

How To Install A Subwoofer And Amp In A Car For many drivers, loud and high-quality sound is one of the most critical options in the vehicle comfort systems need to learn How to install a Sub and amp in car. Often, novice motorists buying a new radio tape recorder are disappointed in its power, although bursting speakers paint on the packaging. Some people try to solve the problem by purchasing more powerful speakers, but the volume becomes even lower. The reason is that the head unit’s output power is not enough to make the speakers in the car sound louder. To solve the problem, an amplifier connects to the audio system. Let’s figure out how it works, what they are, and how to connect it correctly. The most frequently asked questions are: How to install a subwoofer and amp in a car? You will find the answers here in the article.


The name of the device speaks for itself. However, it not only makes the sound from the speakers louder. It allows you to transmit the signal with better quality so that you can hear the difference in the beautiful equalizer settings when playing through this device. For lovers of bass music, a subwoofer can connect to the device. And if you also connect a crossover to the audio system, you can enjoy sound at all frequencies without burning speakers of different power. An additional capacitor in the audio system circuit will not allow the bass to “sink” during peak load on a separate channel. All of these nodes are important for the transmission of high-quality sound. But they will not work correctly unless a more reliable signal gives to them. An auto amplifier performs just this function.


All car amplifiers have three components.


It receives an audio signal from a tape recorder. Each amplifier is limited not only by the output power but also by the input signal’s strength. If it is higher than the input node’s sensitivity, then the music in the speakers will be distorted. Therefore, when choosing a device, it is important to check the signals’ correspondence at the output from the radio and the input to the amplifier – whether they are in the same range.

Power Supply.

This unit is equipped with a transformer to increase the voltage supplied from the battery. Since the audio signal is variable, the voltage in the speaker power supply system must also be positive and negative. The more significant the difference in these indicators, the higher the amplifier power will be. Here’s an example. If the power supply delivers 50V (+25V and -25V), then when using speakers with a resistance of 4 Ohm, the maximum power of the amplifier will be 625 W (the square of the voltage of 2500 V divides by the strength of 4 Ohm). It means that the more significant the voltage of the power supply, the more influential the amplifier.


In this node, a modified audio signal generates and fed to the speakers. It equips with powerful transistors that turn on and off, depending on the signal from the radio. So, this device works according to the following principle. A signal with a small amplitude comes from the head unit of the audio system. The power supply increases it to the required parameter, and an amplified copy of this signal creates at the output stage.


Amplifier in a Car Types

All modifications of amplifying devices divide into two types:


Receive a signal in alternating current and voltage, varying depending on the audio frequency, then amplifying it before going to the speakers;


They work exclusively with signals in digital format (ones and zeros, or pulses in the “on / off” format), increase their amplitude, and convert them into analog form. Devices of the first type transmit sound unchanged. In terms of sound clarity, only live performance can be the best in comparison with analog. However, the recording itself must be perfect. The second type of device slightly distorts the original recording, clearing it from minor noise. You can feel the difference between the two types of amplifiers by connecting them to a turntable. The music lover will opt for the first type of amplifier because the sound in the speakers, in this case, will be more natural (with a characteristic, barely perceptible, needle creak). However, when playing music from digital media (disk, flash drive, memory card), both types of amplifiers work on equal terms. The difference in this sound can be heard in the following video experiment (listen with headphones): The number of channels also distinguishes car amplifiers:


Used to connect a subwoofer with a maximum impedance of up to 2 ohms, often have low-frequency control;


Can be used to connect two speakers or one subwoofer with impedance more than 2 ohms;


Came to replace three-channel because of their impracticality. It type of amplifier is the most common because you can connect either four speakers or two speakers and one subwoofer to them;


Four speakers and one subwoofer connect to them;


They use only if the subwoofer has a higher impedance than the maximum allowable value of the previous modification.


Before installing the device, it is essential to familiarize yourself with some of the nuances on which the car’s safety and the efficiency of the audio system depend.


Several factors depend on the choice of the place of installation of the device.

  • The amplifier gets very hot during operation, so it is essential to choose a location where the best air circulation occurs. It must not mount on its side, upside down, or under the skin. It will overheat the device and, at best, stop working. The worst-case scenario is fire.
  • The farther from the radio it is installed, the more excellent the resistance will be. It will make the speakers sound a little quieter.
  • The wiring must be routed under the interior trim, so it is essential to make the correct measurements for the turns.
  • Do not mount it on the subwoofer cabinet, as it does not tolerate significant vibrations.

Where is the best place to install this audio system element? Here are four more accessible locations. In front of the cabin. It depends on the car model. If there is free space under the torpedo and it will not interfere with the passenger. Its location considers optimal since the maximum sound clarity is achieved (short signal cable length). Under the front passenger seat. There is good air circulation (fresh air always spreads along the bottom) and free access to it. If there is a lot of space under the seat, there is a chance that passengers in the backseat will kick the device with their feet. Rear shelf. Not a bad option for sedan and coupe bodies, because, unlike hatchbacks, it is stationary. In the trunk. It will be especially practical when connecting two amplifiers (one in the cabin and the other in the trunk). Auto electricians advise purchasing wires with a small cross-section margin so that their insulation does not melt due to heating. After such calculations, many are surprised at how thick the wiring for the amplifier will be.


A fuse should be present in any electrical circuit, especially if current with a significant amperage supply through it. It is a fusible element that breaks the circuit when heated up. It will protect the vehicle interior from fire due to the resulting short circuit. The fuse for such systems often looks like a glass barrel with a fusible metal core inside. These modifications have significant drawbacks. The contacts on them oxidize due to which the power of the device is lost. More expensive fuse options equip with bolt clamps that secure the fusible plate. The contact in such a connection does not disappear from constant vibrations during the operation of the motor. This protective element must installs as close to the battery as possible – within 30 centimeters. Modifications that greatly exceed the wire’s capacity cannot use. For example, if the cable is capable of withstanding a voltage of 30A, the fuse, in this case, should not exceed the value of 50A.


It is not the same as a power cable. An interconnect wire connects the audio outputs of the radio and the amplifier. This element’s main task is to transmit the audio signal from the tape recorder to the input node of the amplifier without quality loss. Such a cable should always have strong insulation with full shielding and a thick center conductor. It should purchase separately, as a budget option often includes with the device.


You don’t need to have in-depth electrical knowledge to connect an amplifier. It is enough to follow the instructions that come with the device. Regardless of the modification of the device, the connection is made according to the following scheme.

  1. First, the amplifier case fixed in the car’s chosen place (where it will not overheat).
  2. To prevent the accidental rupture of the line, the wiring should be laid under the interior trim. How to do this is determined by the car owner himself.
  3. However, when laying the interconnect cable, it is essential to remember that location near the power wiring of the machine will distort the audio signal due to electromagnetic radiation.
  4. The power cable can route along with the main car wiring harness. At the same time, it is essential to fix it so that it does not fall under the machine’s moving elements – the steering wheel, pedals, or runners (this often happens if a specialist does not perform the work). In places where the cable passes through the body wall, plastic grommets must use. It will prevent the chafing of the wire. For more excellent safety, the line must laid using tubing (a corrugated tube made of non-flammable material).
  5. The negative wire (black) must fix to the car body. In this case, self-tapping screws and twists cannot use – only bolts with nuts, and the contact point must clean. The terminal on the amplifier marked GND is ground or minus.
  6. The Remote terminal is where the control wire from the radio is connected (it can power from the antenna connector). It sends a signal to activate when the tape recorder turns on. Most often, there is a blue wire or with a white stripe in the kit for this purpose.
  7. The signal cable connects to the Line-out (radio) and Line-in (amplifier) connectors. Many models have several of these jacks: front (Front), Rear (Rear), subwoofer (Sub).
  8. The speakers will connect according to their instruction manual.
  9. What if the radio is two-channel and the amplifier is four-channel? In this case, use an interconnect cable with a splitter. It has two tulips on one side and four on the other.


Low-cost car radio models have conventional connectors with clips. In this case, you will need to purchase a special adapter to connect the line cable. On the one hand, it has ordinary wires, and on the other – “tulip mothers”. The wires between the adapter and the radio tape recorder do not break due to the constant rocking of the device; you can wrap it with foam rubber (it will not rush while driving) and fix it on the head unit case.


Q.1 : Do I need to disconnect the car battery before starting the installation?

Yes, it is extremly advised to remove the battery from your car before starting the installation of a subwoofer and an amplifier. During installation, it is advisable to disconnect the battery in order to avoid any potential electrical to your car’s electrical system.

Q.2 : How do I connect the amplifier to the head unit?

A remote turn-on wire may be required, so make sure you have RCA cables. While the remote turn-on wire allows the head unit to notify the amplifier to turn on/off with the car’s ignition, the RCA cables are utilized to transmit the audio signal from the head unit to the amplifier.

Q.3 : Is it safe to mount the amplifier on the back of the rear seats?

Amplifiers produce heat when they are working, therefore overheating should be taken into consideration. In order to distribute the heat, make sure there is enough airflow around the amplifier coming from the back of the rear seats. Installing the amplifier inside or next to anything that can move air is not recommended.

Q.4 : Can I install multiple subwoofers with one amplifier?

Thus, you may utilize one amplifier to install many subwoofers. The configuration, power level, and impedance (measured in ohms) of the subwoofers you intend to connect to the amplifier determine whether you can accomplish this. The following are some crucial factors to take into account while installing several subwoofers with a single amplifier:


Why you need a crossover and how to set it up is described in the following review:

How to install a subwoofer and amp in a car?

I hope you will understand when choosing an auto amplifier it is necessary to consider that additional equipment requires energy consumption. Therefore it is essential to take care of the reliability of the battery – so that at the most inopportune moment it merely is not discharged. How to check the battery resource can found in a separate article.