The difference between constant resistance and constant pressure
1. Output form difference:
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1. Constant voltage is not a certain voltage, but the output form is a constant voltage, which requires a certain rated voltage of the load. The constant voltage power amplifier is connected by multiple constant voltage speakers in parallel, as long as the total power does not exceed the total power of the constant voltage power amplifier.
2. Constant resistance power amplifier requires a certain output load resistance. In the constant resistance power amplifier, if the load impedance changes, the power will change accordingly. An 8 ohm 100W constant resistance power amplifier connected to 4 ohm will become close to 200W.
2. The application is different in different places
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1. Constant voltage power amplifier is mainly used in public broadcasting in public places, because the distance between public broadcasting speaker and power amplifier is far, and a power amplifier is usually connected to multiple low-power speakers. In order to reduce the line loss and avoid the influence of one speaker on or off on the volume of other speakers in the system, the constant voltage power amplifier has high voltage and low current output. Constant voltage connection power amplifier multiple speakers, as long as the speakers in parallel on an ordinary wire can be.
2. Constant resistance power amplifier. It is mostly used in family background music, home cinema, KTV and stage. Because the distance between the speakers of family background music, home cinema and stage and the power amplifier is relatively close, and it does not need to connect many speakers, so the constant resistance power amplifier has high current and low voltage output. Special speaker cable should be used to connect the power amplifier and sound.
3. Sound quality difference
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Fixed voltage is used in large space where the sound quality is not very high. On the contrary, fixed resistance can only transmit within 100 meters due to transmission limitation, so it is generally used in small space when the sound effect is much better. Because the constant voltage power amplifier uses a transformer in the circuit, its sound quality is affected to a certain extent. But if you choose a high-quality loudspeaker, you can improve the sound quality of the broadcasting system.
Constant resistance power amplifier and speaker, constant voltage power amplifier and speaker need to match:
A simple understanding of constant voltage power amplifier is to use voltage to drive the loudspeaker. It has the characteristics of high output voltage and low current,
Constant resistance power amplifier is our general household power amplifier, which is driven by current. The characteristic of loudspeaker is large current and small voltage
Constant resistance amplifier connected to constant voltage speaker, the sound is very small, even can not hear;
The power amplifier with constant voltage is connected to the speaker with constant resistance, and the speaker is burned;
Speaker size and sound effect:
The larger the diameter of the diaphragm, the larger the volume of air and the more obvious the sound pressure; in short, it is easier to excite the air and give people the feeling of airflow impact. The low frequency response will be better, and the sound felt by the human ear will be better. Of course, it should be matched with power amplifier, power and so on.
The larger the volume, the stronger the magnetism. The stronger the magnetism, the higher the efficiency of the loudspeaker, and the higher the loudness under the condition of the same received power. The more control you have!
Coaxial speaker:
Click on the picture to view the slide mode
Because the general speaker, treble unit and bass unit are arranged on the panel of the speaker, their sound producing centers cannot coincide as one point. In this way, the distance between the treble and bass to the listener is different, which will lead to phase deviation and affect the correct restoration of sound and image. Coaxial speaker uses coaxial unit, which is actually a combination of high pitch unit and low pitch unit. The high pitch is cleverly placed in the center of the low pitch diaphragm, so it can ensure that the acoustic center of high and low pitch is the same point, thus solving the problem of phase deviation.
Frequency division Speaker:
The frequency divider is the "brain" in the speaker, which is used to separate the input music signal into different parts such as high, medium and low, and then send them to the corresponding high, medium and low speaker units for playback.
Click on the picture to view the slide mode
The frequency divider can be divided into two, three and four frequency bands. Bisection is to divide the whole frequency band of audio signal into high frequency and low frequency; trisection is to divide the whole frequency band into high frequency, medium frequency and low frequency; quartering is to divide trisection into ultra low frequency.
The frequency dividing point refers to the intersection of the frequency response curves of two adjacent loudspeakers (such as the treble and bass in the second frequency division, the treble and midrange in the third frequency division, and the midrange and bass). It is usually the frequency at half of the power output of the two loudspeakers (i.e. - 3dB point). It should be determined according to the frequency characteristics and distortion of the speaker and each loudspeaker. Generally, the frequency division points of the two frequency divider are between 1kHz and 3kHz, and the frequency division points of the three frequency divider are 250Hz ~ 1kHz and 5KHz.
定阻与定压之分
1、输出形式区别：
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1、定压不是电压一定，而是输出形式是定压，它要求负载的额定电压一定。定压功放以多个定压音箱并联的形式连接，只要总功率不超过定压功放的总功率。
2、定阻功放要求输出负载电阻一定。 在定阻功放中如果负载阻抗发生变化，功率就发生相应变化。8欧姆100W的定阻功放接4欧姆就变成接近200W。
2、场所应用不同：
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1、 定压功放主要应用于公共场合的公共广播，因为公共广播音箱和功放的距离比较远，而且一台功放机通常要连接多个小功率的音箱。为了减小线路损耗，避免系统中 某个喇叭开启或关闭对其他喇叭的音量造成影响所以定压功放高电压低电流输出〔相对的〕。定压连接功放多个音箱，只要将音箱并联在一条普通的电线上就可以 了。
2、定阻功放.多用于家庭背景音乐、家庭影院、KTV、舞台，因为家庭背景音乐、家庭影院、舞台等音箱与功放的距离比较近而且不需要连接很多的音箱，所以定阻功放高电流低电压输出，连接功放和音响应选用专用的音箱线。
3、音质区别
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定压用在要求音质不是很高的大空间，反之定阻由于传输的限制只能传输100米以内，故一般用在小空间当音效相对要好的多。因为定压功放在电路上使用了变压器，所以其音质受到了一定的影响。但是如果选用优质的广播音箱完全可以提高广播系统的音质。
定阻功放与音箱，定压功放与音箱需匹配：
定压功放简单理解就是以电压来推动扬声器 ，特点，输出电压大 电流小，
定阻功放就是咱一般家用功放 是以电流来推动扬声器的 特点是电流大电压小
定阻的功放接定压的音箱，声音很小，甚至听不到；
定压的功放接定阻的音箱，烧音箱；
音箱尺寸与音效：
尺寸大的音箱单元振膜直径大，推动空气的体积也就越大，声压也就越明显；简言之，就是更容易激动空气，给人有气流冲击的感觉。低频响应会比较好,人耳所感受的的声音会比较好听些。当然还要同功放、功率等等方面都做到相匹配。
吸铁石大体积越大，磁性也越强。磁性越强，扬声器的效率越高，在收到功率相同的的情况下，响度也就越大。，控制力也就越强！
同轴音箱：
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一 般的音箱，高音单元和低音单元由于平面地排列在音箱的面板上，所以它们的发声中心不可能重合为一个点，这样，高音和低音到达聆听者的距离就有差异，这种差 异会导致相位偏差从而影响声像的正确还原。同轴音箱用的是同轴单元，这种单元实际上是高音单元和低音单元的组合体，高音巧妙地放置在低音振膜的中心处，因 此能保证高、低音的声学中心是同一个点，从而解决了相位偏差的问题。
分频音箱：
分频器是音箱中的“大脑”， 用以将输入的音乐信号分离成高音、中音、低音等不同部分，然后分别送入相应的高、中、低音喇叭单元中重放。
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分频器按分频频段可分二分频、三分频和四分频。二分频是将音频信号的整个频带划分为高频和低频两个频段;三分频是将整个频带划分成高频、中频和低频三个频段;四分频将三分频多划分出一个超低频段。
分频点是指两个相邻扬声器(如二分频中的高音与低音，三分频中的高音与中音，中音与低音)的频响曲线在某一频率上的相交点，通常为两个扬声器中功率输出的一半处(即-3dB点)的频率，要根据音箱和每个扬声器的频率特性和失真度等参数决定。通常二分频分频器的分频点取1KHZ~3KHZ之间，三分频取250HZ~1KHZ和5KHZ两个分频点。
