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Instructions – Adjusting / Configuring The Subwoofer


Functionality of a loudspeakerThe construction of a loudspeakerThe best car subwoofers from our review: How is the sound created? Interaction of the loudspeakersHow do I tune the components to each other correctlyThe terms before we adjust the subwooferThe instructions: Adjusting the subwoofer correctly

After successful installation and connection of the subwoofer, the correct setting or configuration of the subwoofer now follows. Before we come to the subwoofer setup and configuration, it is important to understand the theory behind it.

The effect of a loudspeaker is quickly explained: a membrane is made to vibrate and sends sound waves through the air, which are picked up by the ear and processed by the brain.

But how is the membrane made to vibrate?

Functionality of a loudspeaker

The structure of the loudspeaker

At the end of the diaphragm there is a voice coil with a magnet. It starts to move as soon as current flows through the coil. The current can be used to control the length and strength of the pulses. To prevent the diaphragm from moving in all directions, it is fixed at the front side with a bead and at the back side it is

As a result, the diaphragm can only move in one direction and the result is a controlled sound with good efficiency. In addition, there is a basket around the speaker that connects the surround and the magnet. This connects all components with each other.

Briefly introduced the best car subwoofers from our review:

How is the sound created?

The faster the diaphragm vibrates, the higher the frequency and the higher the tone. Humans perceive frequencies in the range from 20 Hz to 20,000 Hz. High frequencies are shrill tones that hurt the ears (used for alarms). Low frequencies are for the low tones that you can only feel but not hear. The car subwoofer moves in a range of 30-160 Hz and is supposed to provide that pleasant feeling in the pit of your stomach. To get an even stronger bass, so-called resonance bodies are used. These resonate with the speaker and produce stronger sound waves with the same power. In the course of time, cabinets have established themselves as resonance bodies. When setting up a subwoofer it is important to understand the principle behind it so that the subwoofer in the car does its job. Namely the reproduction of low frequencies!

Interaction of the loudspeakers

In the car, 2 loudspeakers are installed as standard in the front car doors and usually 2 in the rear doors. Depending on the manufacturer, the installed speakers have a size between 13 and 16 cm. The quality is decisive for a good sound, because only then they can cover the middle and high frequency ranges optimally. A subwoofer is therefore necessary for the low frequencies. The interaction of all frequency ranges ensures the perfect sound experience while driving.

How do I match the components correctly

So that the loudspeakers can only receive their frequencies, there are so-called crossovers (picture). These only allow high frequencies to pass. The low frequencies, on the other hand, are no longer reproduced, which is a good thing. Because these should be reproduced by the subwoofer. The subwoofer has an output stage with which the frequency range can be adjusted. With a good radio you can change the settings directly on the radio. Depending on the music taste, the frequency ranges and basses should be adjusted. For an optimal result there is unfortunately no generally valid setting for adjusting the subwoofer, it only helps to change the parameters more often until the desired result is achieved.

The terms before we adjust the subwoofer

Before I come to the instructions for adjusting the subwoofer, here are a few definitions:

  • Crossover: The crossover is a crossover network. The crossover can be used to switch the individual filters on or off.
  • Lowpass: The lowpass is a filter for the frequencies. It should be set to 100 Hz for the subwoofer. This means that all frequencies above 100 Hz are filtered by the lowpass and do not reach the subwoofer.
  • Subsonic: The subsonic or subsonic filter is a high pass filter. In contrast to the lowpass it filters frequencies below the setting. The subsonic should be at 20 Hz. All frequencies below 20 Hz are no longer perceived by humans. This relieves the subwoofer and improves the sound.
  • Bandpass: The bandpass is a combination of lowpass and subsonic. It allows frequencies in a certain range (bandpass) to pass.
  • Voltage: At the output stage there is usually a so-called gain control, which regulates the input sensitivity. A voltage is sent to the output stage via the RCA cable. The higher the voltages at the pre-amplifier output on the radio, the lower the gain control is turned. But be careful, the higher the Gain control is turned up, the more the subwoofer will start to generate noise! (The signal-to-noise ratio becomes shorter)
  • BassBoost: As the name suggests, BassBoost is designed to boost bass in the bass range. Nevertheless, it should not be changed on the power amplifier, because it will degrade the sound of the subwoofer. On the radio you can easily change the BassBoost a bit, but be careful: if the BassBoost is increased by 6 dB, 4 times the power is needed! (Increasing it by 3 dB means doubling the power) Most power amplifiers cannot deliver the power and therefore distort the sound.

The guide: Setting the subwoofer correctly

And now we come to the adjustment of the subwoofer. Adjusting the volume on the power amp is called leveling, but before leveling, all controls on the radio (BassBoost, Bass or Loudness) must be set to 0 and the gain control on the power amp to the minimum. Next, set the volume of the radio to 3/4 of the total volume and turn the gain control up until the subwoofer starts to overload and distort the sound. Finally, turn the knob back a little (about 1/8 turn) and et violà the subwoofer is set.

And now we come to adjusting the subwoofer. Adjusting the volume at the power amplifier is called leveling, but before you can do that you have to do the following steps

  • Set all radio controls (BassBoost, Bass or Loudness) to 0
  • Set the gain control of the power amplifier to the minimum
  • Now set the volume of the radio to 3/4 of the total volume and turn the gain control up until the subwoofer starts to overload and distort the sound.
  • Finally, turn the knob back a little (about 1/8 turn) and et violà the subwoofer is set.

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