After actually listening to many speakers, it was found that the biggest factor affecting the sound quality of speakers is "resonance tone", which makes the sound quality of speakers turbid and unclear.  

    The "resonance sound" produced by heavy wooden speakers is relatively small.

    2.1 In the speaker box, two small speakers playing medium and high pitch should have holes in the back of the box, so that the low-frequency sound waves can be short-circuited to increase the definition of the medium and high pitch speaker unit. Because the wavelength of low-frequency sound wave is longer, it is easier to bypass the short circuit than high-frequency sound wave.

    The medium and high pitch speakers produced by some companies are totally closed, and the air in the box is repeatedly forced to vibrate, producing "resonance sound" and unclear sound quality.

    The playback purpose of the tweeter unit is to pursue clear vocal and high-frequency sound, the clearer the better.

    2.1 The subwoofer box in the speaker box should not be equipped with an inverted hole, because the low-frequency sound wave contains vibration energy, and the low-frequency sound wave has a long wavelength, which is easy to bypass. If the inverted hole is installed, it is easy to have a "sound short circuit", so the low-frequency will be lost.

    A better solution is to place the subwoofer horn in the middle of the box, or the middle of the subwoofer tube, with the speaker paper basin as the boundary, seal the rear of the horn, and set a sound outlet at the front to limit the emission of low-frequency sound waves.

    Although the closed subwoofer box at the rear of the speaker paper basin is not easy to have "sound short circuit", which reduces the loss of low-frequency vibration energy, the "resonance sound" generated by the closed box is also large. Therefore, in order to improve the sound quality of the subwoofer box, the low-frequency point entering the subwoofer box should be set lower, such as 50 Hz, not more than 80 Hz, and the low-frequency volume should be reduced at the same time, so as not to cause the subwoofer box to produce an unpleasant "buzz" of "resonance sound".

    The tweeter unit should try to eliminate the low frequency entry, while the subwoofer box should try to eliminate the medium and high frequency entry. The greater the polarization, the better, so as to achieve the purpose of frequency division and playback.