Installing high-quality sound in a car often runs into limitations of standard systems or budget head units. Chinese radios based on radios have become incredibly popular due to their versatility and low price, but their audio outputs often raise questions among car audio enthusiasts. The correct connection of an external amplifier or an active subwoofer can radically change the perception of music in the cabin, adding depth to the bass and clarity to the high frequencies. 2 din radios on the base Android have become incredibly popular due to their versatility and low price, but their audio outputs often raise questions among car audio enthusiasts. The correct connection of an external amplifier or active subwoofer can radically change the perception of music in the cabin, adding depth to the bass and clarity to the highs.
The main difficulty is that many owners do not know which output to use: linear RCA or a high-level signal from the speakers. The wrong choice of connection method can lead to extraneous noise, generator hum, or even failure of the built-in amplifier of the radio. In this article we will analyze in detail all stages of connection, from selecting cables to fine-tuning the software on the device under control Android.
Before proceeding with installation, you need to make sure that your equipment is compatible. Most modern Chinese head units are equipped with a standard set of connectors, but the quality of the circuitry can vary greatly depending on the chipset manufacturer (for example Rockchip, Allwinner or MediaTek). Understanding the principles of operation of the audio path will help you avoid common mistakes and get clear, powerful sound without additional costs for installer services.
Diagnostics of audio outputs and selection of connection type
The first step is to carefully examine the back panel of your 2 din recorder. Manufacturers from the Middle Kingdom often use standard color coding for wires, but the location of the connectors may vary. You need to find a group of wires responsible for the audio output. If the rear panel contains round “tulip” type connectors (RCA), usually painted grey, white or orange, then you are in luck - these are linear outputs designed specifically for connecting external acoustics.
If there are no RCA connectors, connection is possible through high-level outputs (wires speakers). This method is less preferable in terms of signal quality, since the built-in amplifier of the radio already introduces its own distortions, but it is fully functional. Modern active subwoofers often have built-in high-level signal converters, which simplifies the task. However, to get the clearest sound possible, it is always better to use a line output.
Pay attention to the number of available channels. Budget models may have only one stereo output (Front), while more advanced versions offer separate outputs for front (Front), rear (Rear) and subwoofer (Subwoofer) speakers. The presence of a dedicated channel Subwoofer greatly simplifies setup, allowing you to control the bass level regardless of the main volume.
⚠️ Attention: Never connect an active subwoofer directly to the power wires of the radio (red and yellow wires). This will lead to instant blown fuses and possible wiring fire. The subwoofer must be powered directly from the battery through a separate fuse.
Necessary tools and materials for installation
High-quality installation is impossible without the correct tools and consumables. Trying to save on wires or using twists instead of soldering will inevitably lead to signal loss and the appearance of oxides in the future. To work, you will need a set of basic tools, as well as specialized components for organizing the audio path and power supply.
Particular attention should be paid to the choice of interconnect cable. Cheap options with a thin screen often become a source of interference from the car's ignition system. It is recommended to use cables with dense braiding and high-quality connectors. The cross-section of the power wires is also critically important: for a subwoofer with a power of up to 500 W, a cable with a cross-section of at least 4 Ga (sq. mm) will be optimal.
- 🔧 Set of screwdrivers and pullers for plastic car panels.
- ✂️ Stripper for stripping wires and wire cutters.
- 🔌 Interconnect cable (RCA-RCA) long enough for laying from the glove compartment to the trunk.
- ⚡ Power wire (plus) with a fuse bulb and ground wire (minus).
- 🛠️ Heat-shrinkable tubes or electrical tape for insulation connections.
- 📏 Multimeter for checking voltage and continuity of circuits.
When laying wires, avoid places where they can rub against the metal of the body or be exposed to high temperatures. Using corrugated pipe or conduit will greatly increase the longevity of your system. Do not forget that the power cable and the interconnect audio cable must be laid separately, preferably on different sides of the cabin, to eliminate electromagnetic interference.
Active subwoofer connection diagram
The connection process can be divided into three main stages: power supply, audio signal connection and switching control. The most common mistake made by beginners is ignoring the control wire (REM). Without the correct connection of this wire, the subwoofer will not turn on along with the radio, or will work constantly, draining the battery.
The power plus (+12V) is taken directly from the battery terminal. A fuse must be installed in the wire gap, at a distance of no more than 30 cm from the battery. This is a security requirement that cannot be ignored. The ground wire (GND) should be attached to the metal body of the car in the immediate vicinity of the subwoofer, having previously cleaned the contact area until the metal shines to ensure reliable grounding.
To transmit an audio signal, use a prepared interconnect cable. One end is connected to the corresponding output Subwoofer or Rear on the radio, and the second to the input Line In on the subwoofer body. If you use a high-level connection, then the wires from the radio speakers are connected to the input High Level Input on the subwoofer, observing the polarity (plus to plus, minus to minus).
| Wire color (ISO) | Purpose | Where to connect on the subwoofer | Note |
|---|---|---|---|
| Blue / White-blue | Remote Turn On (REM) | REM terminal / Turn On | Turn-on signal (12V when the GU is turned on) |
| Gray / White (RCA) | Audio Out (Sub/Rear) | RCA input (L/R) | Audio signal transmission |
| Red / Yellow | Power +12V | Not connect directly! | The subwoofer is powered only from the battery |
| Black | Ground (GND) | Car body (next to the subwoofer) | Reliable contact with metal |
If your radio does not have a dedicated subwoofer output, use the rear speaker outputs (Rear). In the settings of the Android head, you can programmatically redirect frequencies or use a subwoofer filter.
Setting up software on Android
After the physical connection, the software configuration stage begins. Chinese radio tape recorders Android have extensive sound settings, which are often hidden in the depths of the menu. The standard equalizer may not be effective enough, so you should look for advanced settings or third-party applications.
Go to the sound settings menu (Settings → Sound or Car Settings → Audio). Find the section responsible for frequency distribution. You need to activate the mode Subwooferif there is such a switch. In some firmware this parameter is called Sub Out or Low Pass Filter (LPF). Activating this mode turns off low frequencies on the main speakers and transfers them to a separate output.
For finer tuning, it is recommended to install an application like PowerAmp or a specialized equalizer from Google Play. They allow you to create an individual frequency response curve (FRC), removing the “mumbling” and leaving only elastic bass. In a standard equalizer, try lowering the frequency sliders at 60 Hz and below if the sound seems washed out, and raising the 80-100 Hz region for impact.
⚠️ Note: The audio settings interface may vary depending on the firmware version and processor model. If you do not find the desired item in the standard menu, check the “Factory Settings” section, but be careful: changing other parameters there may lead to incorrect operation of the radio.
Access codes for factory settings
Often a password is required to enter the extended menu. Common combinations for Chinese 2 din radios: 8878, 1234, 5678, 0000, 1617. Enter them carefully, without changing settings that you are not sure about.
Eliminating noise and background in an audio system
The appearance of extraneous noise, whistling or hum after connecting a subwoofer is a common problem associated with a “ground loop” or poor-quality shielding. A hum, the frequency of which changes with engine speed, usually indicates a grounding problem or interference from the generator to the interconnect cable.
The first thing to do is check the ground connection point of the subwoofer. It should be as short as possible and attached to the stripped metal of the body. Avoid attaching the mass to plastic elements or areas covered with paint. Also make sure that the interconnect cable is not laid close to the subwoofer power wire along the entire route.
If the problem is not solved, try disconnecting the power to the radio from the total mass of the car and supplying the negative wire with a separate wire to the same point where the subwoofer ground sits. This equalizes the potentials and breaks the earth loop. In extreme cases, installing a decoupling filter (Ground Loop Isolator) into the interconnect cable gap helps, although this may slightly degrade the sound quality.
- 🔍 Check the reliability of the subwoofer ground contact (stripping to metal).
- 🔌 Place the power and interconnect cables on different sides of the cabin.
- 🔋 Make sure that the battery and generator are in good condition (voltage sags cause interference).
- 🎚️ Try changing the position of the wires relative to each other at the intersection points.
90% of background problems in the system are solved by proper grounding and separation of power and signal lines. Do not rush to buy expensive filters until you check the ground.
Frequency calibration and phasing of speakers
The final touch is setting up the crossover and checking the phasing. Incorrect phase causes the subwoofer cone to move out of phase with the main speakers, causing mutual cancellation of low frequencies. The sound becomes flat and lacks volume, despite the high power of the system.
To check the phasing, turn on music with a pronounced bass line and ask an assistant to alternate the polarity of connecting the wires at the subwoofer terminals (+ and -). When positioned correctly, the bass should sound loudest and most focused, as if it were coming from the dashboard rather than the trunk. If the sound becomes better when changing the polarity, it means that the wires were initially connected incorrectly.
Adjust the low-pass filter (LPF) on the subwoofer housing or in the radio settings. The optimal cutoff is usually in the range of 60-80 Hz. The subwoofer should not reproduce frequencies above 100 Hz, as this will create localization of sound in the trunk, which is unacceptable for high-quality stereo. Smooth adjustment will allow you to find a balance between “beats” and deep “undertones.”
⚠️ Attention: Prolonged playback of music at maximum volume with an incorrectly configured crossover can lead to thermal breakdown of the subwoofer coil. Start tuning with a minimum volume, gradually increasing the Gain level on the amplifier until distortion appears, and then reducing it slightly.
☑️ Final system check
Is it possible to connect subwoofer to the radio without a separate REM wire?
Yes, this is possible, but less convenient. You can connect the control wire (REM) of the subwoofer to the positive power wire of the radio itself (usually the red or yellow wire going to the ignition switch or permanent positive through the lock). In this case, the subwoofer will turn on automatically when power is supplied to the head unit. However, this method can lead to clicks when turning on/off and does not allow you to control the subwoofer independently.
Why does the subwoofer hum at idle speed of the engine?
This hum is called “alternator whistling” and is caused by interference from the ignition system or poor-quality grounding. Most often, the problem is solved by moving the amplifier's grounding point to another location in the body or installing a power supply noise filter. Also check if the audio cable is laid near high-voltage wires or the engine control unit.
Which wire to use to connect the ground: as thick as the plus?
Yes, the cross-section of the ground wire should be identical to the cross-section of the power positive wire. Using a thin wire for ground will create a bottleneck in the power circuit, which will lead to a voltage drop, overheating of the wire and loss of power to the amplifier. For a system up to 500 W, use 4 Ga (mm2) wire for both lines.
How to set up a subwoofer if there is no Subwoofer item in the Android menu?
Use the rear speaker outputs (Rear). Connect the subwoofer to these connectors (via a converter or directly if the sub is active with a high-level input). Then in the sound settings of the radio, set the balance (Fader) all the way back so that the sound comes only to the rear. To filter frequencies, use the control LPF on the subwoofer body itself.
Does the length of the interconnect cable affect the sound quality?
Theoretically yes, but in practice in a car the difference between a high-quality cable 3 meters long and 5 meters long is invisible to the human ear. The main thing is the quality of the cable shielding, not its length. Avoid excessively long cable loops in the trunk, as they can act as an antenna, collecting interference. Twist the excess into neat rings.