How to turn a home subwoofer into a car subwoofer
When connecting a home subwoofer to a car, you need to know that the output power will not be very high. Most home low-frequency speaker systems are not designed for the kilowatt load that audiophiles love so much. In addition, the home speaker box is not designed to operate in conditions of constant shaking and vibration. The same applies to the loudspeaker. Home acoustic equipment is operated under conditions of normal temperature and humidity, so there will be many reasons for the failure of such a system installed in a car. Installing a home subwoofer in a car is not the best idea. The main thing is that a home low-frequency speaker is designed for voicing large volumes. The most modest room is tens and hundreds of times larger than the volume of the luggage compartment of a car, so the loudspeaker will not sound at all as desired. Speaker cones for household speaker systems are not designed to withstand extreme temperature changes and high humidity. Most car dynamic head diffusers are made of polypropylene and other synthetic materials that do not absorb moisture at all. Of course, you can install a home subwoofer in your car, but most of such technical solutions do not differ in sound quality and durability.
Which subwoofer should I choose to work with the built-in amplifier of the radio?
We sorted out the radio. Now let's move on to the subwoofer. We will need a subwoofer with low power but high sensitivity. Any cabinet subwoofer like “Magnat 301” from the Bull Power series will do. Of course, this is not the best option, but it is suitable for our installation.
Now a few words about sound quality. We tried to reproduce this connection option on a stand with a Pioneer DEH 4500 radio and subwoofer. Initially, we expected that nothing would work and the sound quality would be disgusting, but after assembling the entire circuit, we were pleasantly surprised. The bass was certainly not like that of top-end installations with expensive components, but quite noticeable and pleasant.
From this we can conclude that it is quite possible to connect a passive subwoofer to a radio without an amplifier, the main thing is to have a radio that has a separate output to the subwoofer or has the ability to work in bridge mode, and a subwoofer of low power but with high sensitivity.
Connecting a home subwoofer to a car
To connect a home subwoofer to a car, you will need the same connecting cables as for car speakers. Typically, a household low-frequency speaker has a low-frequency amplifier mounted and there are sockets for connecting two satellite speakers. Some home models do not have an amplifier, but instead consist of a bass speaker installed in a casing made of multi-layer plywood or MDF. Such a passive channel can be connected directly to the car radio instead of rear speakers. Most home low-frequency speaker systems are made using a bass reflex design. This means that the housing has a resonator in the form of a plastic cylinder. For this design to work correctly, there must be free space in front of the bass reflex hole.
Installing a home subwoofer in a car is no different from installing a special car system. Connecting cables must be laid through technological openings in the car body. At the points of intersection of metal planes, plastic bushings must be placed on the speaker wires. This will prevent damage to the cable insulation from vibrations while the vehicle is moving. Installing a home theater subwoofer in your car will most likely not give the desired result. If in a living room such a speaker provided rich and rich bass, then placed in the luggage compartment of a car it will work much worse. The sound of such speaker systems becomes booming and smeared. Often an active home subwoofer in a car is used from a personal computer. This is a compact acoustic speaker with a built-in low-frequency amplifier and contact blocks for connecting two small-sized full-range speakers.
The main difficulty in connecting an active home subwoofer to a car is that the chips on which the device is made require bipolar power. Therefore, simply cutting off the tracks leading to the power unit and connecting the built-in amplifier to the car battery will not work. Such circuit solutions are used in the popular active speaker system SPS-820. The integrated circuit can be powered from a single-supply power supply, but the output power will be too small even compared to the front speakers. With such power, there is no point in installing a separate bass channel.
How to connect a 220 volt subwoofer to a car
There are two ways to connect a home subwoofer to a car. If the built-in low-frequency amplifier is powered by a unipolar 12-14 volt source, then there will be no problems. You just need to cut the tracks going from the diode bridge to the filter capacitor, and solder the wires from the car battery to these points. The second method allows the use of only a subwoofer. You need to find the connection points for the speaker to the output elements of the amplifier or unsolder the wires going directly to the speaker. Next, a low-frequency signal from the car radio is supplied here. If the home low-frequency channel has high output power and high quality, then connecting a home subwoofer to a car will involve installing a converter.
This electronic device converts DC battery voltage into AC 220 V. The best option is to use an industrial converter. But it makes no sense to purchase an expensive product to power a low-power low-frequency channel. Therefore, on many forums the idea of installing a 220 V subwoofer in a car is criticized. If you have experience in amateur radio, you can make a 12/220 converter yourself.
There are simple circuits of voltage converters with field-effect transistor switches. To power an automotive active low-frequency channel, you can use the following circuit. The multivibrator is made using powerful transistors, and other types of field-effect transistors can be used as switches. IRFZ46, IRFZ48 or IRF3205 will do. The transformer is taken ready from an uninterruptible power supply. The converter provides power of 250-300 watts. If you increase the number of switches connected in parallel, you can get twice the power. To install a home subwoofer with an amplifier in a car, you need to lay a high-quality power line.
Built-in radio amplifier
Most likely, your radio tape recorder produces 40-50 watts per channel (as it should be written on it - in real life there is no more than 20 watts), which means that in order to connect the subwoofer directly to the radio tape recorder, you need to connect two channels using a bridge circuit.
Some modern radios have an output to a subwoofer in their main connector, as well as to other speakers. It is worth reading the instructions for your radio to find out; if you have such an output, then you are lucky and the subwoofer can be connected like a regular speaker; in our case there was no such output.
Let's take Pioneer radios as an example. Starting from the 4000th series, the manufacturer began to indicate in the instructions that the maximum power of the radio can be 4×50 (4 Ohm) (This is when using two front channels + two rear channels), or 2 x 50 (4 Ohm) and 1 x 70 (2 Ohm) . From these data we can conclude that 2 rear channels can be combined into a bridge.
Also in the settings of the radio itself there is a manual adjustment of the amplifiers of the rear channels, which, in addition to all modes, has a switching mode via a bridge circuit, which is called Sub.
Install a home active subwoofer in your car
Connecting a home subwoofer to a car involves some difficulties. First of all, this is the choice of power supply system. The next issue that will have to be addressed is the reliability of the entire low-frequency system. Due to shaking and vibration, all wire lines must be securely secured in their sockets. To connect speaker systems in home equipment, spring terminal blocks are often used. They are quite reliable for stationary equipment, but are completely unsuitable for speakers that will be used in a car. In order to avoid inadvertent shutdown of elements of the low-frequency path, you will have to convert your home subwoofer into a car. First of all, you need to replace all spring connectors with screw terminals. To do this, the end of the wire is stripped, a closed loop is made on it, which is tightly tightened under the nut.
The next issue that will have to be addressed is the appearance of the speaker system. Home low-frequency speakers are usually finished with expensive wood veneer. When the device is intended for installation in the luggage compartment of a car, then a prestigious appearance is completely unnecessary and nothing will remain of a beautiful coating in a short time. To give a home subwoofer in a car a decent appearance, its coating will have to be redone. Carpet is considered the best material for covering car speaker systems. This is a non-woven synthetic material with a number of advantages:
- Resistant to fading
- Does not accumulate dust and dirt
- Antistatic
- Not susceptible to moisture and mold
- Retains its properties for a long time
The material is easy to cut with scissors, and to paste the low-frequency speaker, you can use any adhesive, including regular PVA glue.
In order to properly connect a home subwoofer to a car, you need to take care to protect the case from high humidity. To do this, you need to remove the back wall of the speaker and coat all the seams on the inside with silicone sealant. After the composition has completely dried, the procedure can be repeated.
Home active sub in the car
It is necessary to convert a home subwoofer into a car only if the power of the low-frequency dynamic head is comparable to the power of the internal speakers installed in the car. A small desktop sub used for personal computers has little power and will not be able to give the desired effect. In this case, you won’t get rich and rich bass, and money and time will be wasted. To avoid organizing power connections, you can try connecting a passive home subwoofer to your car. If the home theater speaker is equipped with a powerful and high-quality speaker, it makes sense to purchase a single-channel low-frequency amplifier to connect the system. It should be installed next to the speaker system in the luggage compartment of the car.
What will you need?
To install a passive subwoofer without an amplifier yourself you will need:
- speaker cables required for switching;
- plastic buffers to hold the woofer housing in the luggage compartment of the car;
- plastic screwdriver for removing plastic interior trim;
- side cutters for cutting cables;
- plugs needed for connection;
- PVC tape or protective tube;
- flexible clamps;
- protective corrugated tube for laying cables.
Before starting installation work, you should make sure that the purchased equipment is compatible. Connecting speakers with inappropriate coil resistance causes the radio amplifier to overload, which damages the device. If the player has a security code, you need to make sure it is there. Otherwise, after connecting the battery to the on-board network, it will not be possible to restore the radio’s functionality.
