How to use a good sound system amplifier (3)

I. Amplifier and speaker connection method we all know, speakers have speakers nominal power, and this power in practice, the signal voltage is not always a frequency of the sine wave, but can be decomposed into a number of harmonics of the composite wave, and its average power is not the average power of sinusoidal conditions; the second output mode of the amplifier, we analyzed the stereo output, parallel output and bridge output of the three modes, exactly! How should we choose? Third. The output impedance of the amplifier and the input impedance of the speaker has a different meaning, is the same good or try to choose a small impedance of the speaker is good? And so on. Therefore, to understand the amplifier and speaker connection is a good amplifier must know. 1, power matching in accordance with our general understanding, the power of the amplifier and speaker equal is the most reasonable, the most secure, in fact, it is not. Due to the definition, test the output power of the amplifier, is the average power rating using a sine wave, while most speakers work in the amplified audio signal state, which is non-sinusoidal state, taking into account the audio signal we more pink noise to replace the pink noise signal, and pink noise signal peak level than the average of the sine wave signal to be 6 times larger, and to ensure that the peak signal complete amplification (not clipping), that is, the requirements of the amplifier's Output power must be 6 times the power of the speaker, of course, this is more extravagant, most speakers in general will not work in the rated power state. We can choose 2 times, but not less than the power of the speaker. We know that the rated output power of the amplifier is the maximum undistorted power (distortion must be), when we increase the strength of the input signal, the amplifier's output signal will also increase, but at this time, its distortion is rapidly increasing. From the working state of the amplifier tube is saturated, from the waveform analysis is generated by the elimination of distortion. That is, when the input is a sine wave, the output is close to the square wave waveform. Further from the theoretical analysis, such a waveform according to the Fourier series expansion, there are a large number of high-frequency harmonics. Thus, the speaker's treble head is a great impact, most of the voice coil will be burned off. 2, frequency matching nowadays, the amplifier, its frequency response can be easily done to 20 ~ 20K, but most of the general speakers can only be done to 80 ~ 16K, very few can be done to 20 ~ 20K, therefore, we are working in the system, should not be and do not have to work on the frequency response of the amplifier in 20 ~ 20K, but with the help of the peripheral equipment for low cut or high cut. Peripheral equipment for low cut or high cut to adapt to the bandwidth of the speaker, so that the sound becomes good. 3, impedance matching amplifier and speaker have their own nominal impedance value, as already mentioned. The smaller the impedance of the speaker, the greater the output power of the amplifier, but then the amplifier has a greater impact, mainly the output power and stability. Amplifier output power increases, means that the current flowing through the amplifier tube increases, at this time, the temperature of the amplifier tube to rise, the temperature rises, the reliability of the amplifier tube to decline; on the other hand, due to the existence of the amplifier's internal resistance and resistance of the line, speaker impedance decreases, the relative increase in line loss, which directly leads to a reduction in the power obtained by the speakers, resulting in a decline in efficiency, and therefore require the two impedances to be matched, generally with a 8Ω or 4Ω Speaker is more appropriate, too big or too small are not good (especially when more than one speaker series, parallel).