Audio Source (Audio Source)
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In a broad sense, as long as the sound can be produced as a sound source, the sound is that as long as it is an interface that can generate sound and convert it into an electrical signal, it can be called a sound source, such as a CD. LP, audio tape, FM/AM radio, microphone, etc. are all sound sources, but only the sound source has no way to produce the sound we can hear. The signal must be transmitted through the relevant medium, and the expansion can be heard by our ears. The sound that comes.
Preamplifier
What is the pre-stage (preamplifier), the pre-stage is after the audio source, the device before the power amplifier is called the pre-stage, simply the pre-stage is a "control signal" device, such as EQ, DSP, Line Driver, Electronic crossovers and so on, so many things must be loaded one by one? In fact, it is not necessary, because in fact there are many pre-level functions that have been included in the host or the post-level. Just like some functions on the mainframe, don't tell you that you still don't know that he is a predecessor! Like the control interface of CD and TAPE signals, if the car audio host has no control interface, then you don't have to be like home audio. A machine, a machine is moved to the car, and you must also have a sound source to pick up an amplifier, so that you are crazy when you have not yet heard the sound. Let me introduce a few preamp functions that are included in the general car audio host:
Volume control or signal control (Volume Select, signal), generally use a variable resistor that can change the resistance to change the voltage value of the output signal to control the volume (signal). If you don't have these control interfaces, then the sound you hear will be the maximum expansion, then your device is broken, or your ears are broken.
Front and rear, left and right balance control (Fader, Balance), its working mode is similar to the volume control, just to respond to the difference between the speaker or the amplifier, or because of the asymmetric speaker installation position on the car. Tone sound quality control is designed to allow the sound quality to be adjusted to suit your own preferences, but this feature has been replaced by other additional features of the current host.
Loudness (Lordness Gain) When we listen to music, sometimes we can't hear low frequencies like 100Hz or high frequencies at low volume. The loudness gain is lower when we turn on Loudness. The frequency band and the higher frequency band make a gain action, so that you have a feeling that the sound effect seems to be better, but the response is less uneven than the full frequency response, and will make you feel high at high volume. Ears and bass are blurred. These are the pre-level functions that will probably be available on the average parity host. The next step is to introduce the pre-levels that are currently sold independently.
Line Driver (also known as Pulse, signal amplifier)
The function of the Line Driver signal amplifier is to send the signal to other pre- or post-stage signals to make the amplification gain. At present, the general post-stage (power amplifier, under standard conditions, the 1V signal input can be fully opened. The output, so basically the Line Driver must at least achieve a low distortion output of 1V), but considering the large dynamic range, it is necessary to add the Line Driver to amplify the signal.
EQ (Equalizer, equalizer)
The main function of EQ is to compensate for the poor sound listening environment, not to absorb sound or reflected sound, but to make the treble too sharp, the bass is too fuzzy, generally the frequency that people can hear is 20Hz~ 20KHz, and EQ divides this range into a number of frequency bands, and then gains or attenuates some of the affected frequency bands to achieve better sound effects.
In fact, some mid-priced hosts have already added the above-mentioned pre-levels, but these functions are independent because of the insufficiency of the host. However, some of the higher-priced host groups on the market are almost Include all the features, maybe we should think about whether these predecessors still exist.
DSP
Digital sound processor, this machine uses the digital signal to program, and some space, such as in the opera house, to reduce the use frequency to create the sound field effect, or to turn the song into Jazz, The musical feelings of Pop and so on, these are the masterpieces of DSP.
Electronic crossover
The function of the electronic crossover is used to cut the signal of the full-frequency signal. Since the speaker has certain physical characteristics, the small speaker can only produce a higher frequency band, and the large speaker is a lower frequency band, so it is necessary to The splitter is used to cut and distribute to the amplifier, and then to the amplifier and speaker to emit the sound that is appropriate.
After the stage (Power Amplifier, power amplifier)
The function of the pre-stage is to amplify the voltage of different signal strengths into a voltage of sufficient strength to drive the power amplifier (hereinafter referred to as the amplifier). The function of the amplifier is to amplify and amplify the signal amplified by the preamplifier, so that the amplifier has enough power to push the horn. Generally, we must at least meet the following conditions when choosing an amplifier: First, the sound/Noise Ratio (S/N ratio), second, not easy to be distorted, and third, the speaker can be driven (this is the most important). Fourth, high stability, five, the price is reasonable and meet your requirements.
The expansion machine is classified into A, B, C, D, G, etc., which is classified according to his work characteristics, instead of saying that he is A or A, and we are in car audio. I can see about these types of A, B, AB, and D. I will briefly describe their advantages and disadvantages. Class A: low distortion, but the efficiency is too low, about 20% to 30%, easy to overheat, generally low. Power amplifier. Class B: Easy to be distorted, the efficiency is about 60% higher. Class AB: The working characteristics and efficiency are between A and B. Class D: Using Modem (this is not a modem, here is a circuit technology for modulation and demodulation) to expand the signal, and then use the computing chip to reply to the signal waveform, the efficiency can reach more than 90%, less heat .
Speaker (Speaker)
The horn is a very important device in the audio equipment. Without him, he can't reproduce the sound you want to hear. It is also the last and final equipment in the audio. You must understand that the function of the horn is to make the electrical signal into the adult ear. The sound that can be heard is about 20Hz-20KHz at the general frequency. However, in the current speaker brand, it can be said that there is almost no speaker that can have a complete, flat and full range, which is caused by physical characteristics. The low frequency response of the speaker with good high frequency response naturally becomes worse. The special speaker design is not limited to this, such as electrostatic speaker, flat speaker, ribbon speaker. Therefore, in the market, a combination of speakers of a group of more than one monomer is generated, such as a treble, a bass is called a two-way, a high, a medium, and a low is called a three-way.
The horn should show the sound quality, tone and volume in the car. It is more difficult than the home audio, because the installation position is not good, the listening position is more asymmetrical, plus many decoration factors that cause sound absorption and reflection effects. The resulting resonance, standing wave, time difference, phase shift, phase difference and other unfavorable factors, so a university is asked to install the car audio.
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