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car audio Knowledge entry – Features – Category articles: detailed description of the characteristics of car audio and automotive listening environment knowledge. The following order by the purchase shopping network, available to you for reference.

The characteristics of car audio and car listening environment

First, the characteristics of car audio

Car audio and home audio functions basically the same expensive than home audio, car audio than it is because the more unique home audio.

1) small form factor.

By the vehicle dashboard area restrictions, car audio smaller. In a limited volume, car audio technology to achieve the design requirements, the cost will be high.

2) and appalling conditions.

Different levels of car driving on the road, the car stereo will be subject to vibration and shock, so the car to use more tape playback part of the lateral placement of the upper and lower clamping to ensure stable playback. CD part of the multi-stage damping measures, the CD in advance of the release of the information stored in the chip 3s, CD player by a strong vibration, the laser head should be protected to stop working, then release the information stored in the chip, so do not feel playback stutter or skips. Car audio components in the welding assembly to be absolutely solid, the individual components need to use more powerful limbs fixed. Car audio to be able to withstand the outdoor temperature changes (under the dashboard in the sun the temperature can reach 70-80 ℃, cold regions of up to minus 30-40 ℃), so the level of components required is high. Car audio for the prevention of moisture should have a certain measure, generally in the component surface coating agents moisture protection circuit, so that the lower part of car audio in different environments to work properly.

3) the use of low-voltage DC power supply.

Large passenger cars, trucks and more car audio power supply system for the 24V, 12V passenger cars use more power, voltage change will directly affect the audio output power. Power amplifier using switching power supply voltage to the step-up method 35-40V, the voltage fluctuations can guarantee the stability of output power. Car audio amplifier with high current linearity, saturation hold the line, high efficiency, and has overheated, over-current, short circuit protection. .

4) anti-interference ability.

Automotive engine ignition system and a variety of electrical appliances and car stereo with a common battery, it will through the power lines and other lines of audio interference. Of power line interference, can choke the string in the filter between the power and sound; of spatial radiation interference, can be sealed using metal shield isolation. In the high-end audio is also equipped with a special integrated circuits and components for anti-interference, to reduce the external noise.

5) The radio part of the high sensitivity.

Car on the road, both the external environment have changed the direction of impact (such as tall buildings, bridges, cable networks, etc.), to ensure the normal radio, the radio part of the required sensitivity, selectivity, S / N (signal / noise) ratio are high performance, the AGC (automatic gain control) and AFC (Automatic Frequency Control) requirements are high. Mechanical radio tuner and more sense to use tone mode, vibration and tuned to enhance the stability of the FM (frequency modulation) band of the coordination requirements of stable and reliable. Advanced use of digital sound synthesis has been coordinator.

In addition, there are many car audio home audio features are not available, such as: operating instructions with voice control of audio, hands-free control just talking to complete the operation; steering wheel audio controls mounted on the status of various work button, you can also hand steering wheel audio controls; advanced audio capabilities in the voice prompts (VOICEGUIDE) and so on. Some of the speed of sound pressure according to the speed of human eardrum pressure changes generated automatically increase or decrease the volume potential, so that passengers do not feel the volume change. Wind and engine noise makes it difficult to capture the details of music, in order to overcome this problem using dynamic road noise control, dynamic road noise control (DRC) can enhance the bass and treble, but also increase the soft music section.

Second, the car listening environment

As the car s own characteristics, vehicle listening environment with the following results on the listening adverse effects:

1) car interior volume of only a few one-tenth of the general room, and car interior with obstacles of various shapes, sounds are not well spread, will result in a hearing on the oppressive.

2) General room or concert hall reverberation time-bit 300-1000ms, and the car interior of the reverberation time in 100ms or less, very short, resulting in lack of reverb, presence at the hearing is not easy to generate a long time will produce fatigue.

3) The home stereo system to listen to the speaker s position relative to the symmetrical position, and location of car audio system for listening to the speaker s position is very asymmetric, rising tone in the auditory field will tend to listen to those close to the speaker position direction.

4) a variety of materials for sound absorption is different, and the same material for each frequency absorption are different, so even if the same types of vehicles, materials and decorations will be due to internal differences in the number of sound effects .

General interior decoration, car seat, roof and floor surface materials such as cloth and blankets, the inside of the use of synthetic leather, with listening and glass effects, in the middle and the formation of more complex high-frequency acoustic characteristics. Leather interior decoration of the absorption of sound is smaller than the cloth, therefore, the use of leather upholstery of cars, in the hearing, the high-frequency listening was better.

5) car-specific noise, such as traffic noise and vibration, engine noise, tire noise traveling, listening for the sound effects will have a negative impact, particularly on the impact of low-frequency range, thereby undermining the sense of the intensity of sound and music. As the speed increases, the noise gradually to the high frequency part of the expansion will cover the low-frequency noise driving the sound field, so the sound quality deterioration. Car audio by car driving noise is very large, usually can feel the phenomenon: when the car is moving low-frequency domain than in the stopped state appears inadequate, as the speed increases, the frequency will become deficient.